diff --git a/api/v1/announcements/PKPAnnouncementHandler.php b/api/v1/announcements/PKPAnnouncementHandler.php
index f1730a2d54c..d0f2a48a3e1 100644
--- a/api/v1/announcements/PKPAnnouncementHandler.php
+++ b/api/v1/announcements/PKPAnnouncementHandler.php
@@ -18,9 +18,11 @@
 namespace PKP\API\v1\announcements;
 
 use APP\core\Application;
+use APP\core\Request;
 use APP\facades\Repo;
 use Exception;
 use Illuminate\Support\Facades\Bus;
+use PKP\context\Context;
 use PKP\db\DAORegistry;
 use PKP\facades\Locale;
 use PKP\handler\APIHandler;
@@ -92,6 +94,10 @@ public function __construct()
      */
     public function authorize($request, &$args, $roleAssignments)
     {
+        if (!$request->getContext()) {
+            $roleAssignments = $this->getSiteRoleAssignments($roleAssignments);
+        }
+
         $this->addPolicy(new UserRolesRequiredPolicy($request), true);
 
         $rolePolicy = new PolicySet(PolicySet::COMBINING_PERMIT_OVERRIDES);
@@ -163,7 +169,7 @@ public function getMany($slimRequest, $response, $args)
             }
         }
 
-        $collector->filterByContextIds([$this->getRequest()->getContext()->getId()]);
+        $collector->filterByContextIds([$this->getContextId()]);
 
         Hook::call('API::submissions::params', [$collector, $slimRequest]);
 
@@ -188,17 +194,14 @@ public function add($slimRequest, $response, $args)
     {
         $request = $this->getRequest();
         $context = $request->getContext();
-
-        if (!$context) {
-            throw new Exception('You can not add an announcement without sending a request to the API endpoint of a particular context.');
-        }
+        $contextId = $this->getContextId();
 
         $params = $this->convertStringsToSchema(PKPSchemaService::SCHEMA_ANNOUNCEMENT, $slimRequest->getParsedBody());
         $params['assocType'] = Application::get()->getContextAssocType();
-        $params['assocId'] = $request->getContext()->getId();
+        $params['assocId'] = $contextId;
 
-        $primaryLocale = $context->getPrimaryLocale();
-        $allowedLocales = $context->getSupportedFormLocales();
+        $primaryLocale = $context ? $context->getPrimaryLocale() : $request->getSite()->getPrimaryLocale();
+        $allowedLocales = $context ? $context->getSupportedFormLocales() : $request->getSite()->getSupportedLocales();
         $errors = Repo::announcement()->validate(null, $params, $allowedLocales, $primaryLocale);
 
         if (!empty($errors)) {
@@ -208,54 +211,11 @@ public function add($slimRequest, $response, $args)
         $announcement = Repo::announcement()->newDataObject($params);
         $announcementId = Repo::announcement()->add($announcement);
         $sendEmail = (bool) filter_var($params['sendEmail'], FILTER_VALIDATE_BOOLEAN);
-        $contextId = $context->getId();
-
-        /** @var NotificationSubscriptionSettingsDAO $notificationSubscriptionSettingsDao */
-        $notificationSubscriptionSettingsDao = DAORegistry::getDAO('NotificationSubscriptionSettingsDAO');
-
-        // Notify users
-        $userIdsToNotify = $notificationSubscriptionSettingsDao->getSubscribedUserIds(
-            [NotificationSubscriptionSettingsDAO::BLOCKED_NOTIFICATION_KEY],
-            [PKPNotification::NOTIFICATION_TYPE_NEW_ANNOUNCEMENT],
-            [$contextId]
-        );
-
-        if ($sendEmail) {
-            $userIdsToMail = $notificationSubscriptionSettingsDao->getSubscribedUserIds(
-                [NotificationSubscriptionSettingsDAO::BLOCKED_NOTIFICATION_KEY, NotificationSubscriptionSettingsDAO::BLOCKED_EMAIL_NOTIFICATION_KEY],
-                [PKPNotification::NOTIFICATION_TYPE_NEW_ANNOUNCEMENT],
-                [$contextId]
-            );
-
-            $userIdsToNotifyAndMail = $userIdsToNotify->intersect($userIdsToMail);
-            $userIdsToNotify = $userIdsToNotify->diff($userIdsToMail);
-        }
-
-        $sender = $request->getUser();
-        $jobs = [];
-        foreach ($userIdsToNotify->chunk(PKPNotification::NOTIFICATION_CHUNK_SIZE_LIMIT) as $notifyUserIds) {
-            $jobs[] = new NewAnnouncementNotifyUsers(
-                $notifyUserIds,
-                $contextId,
-                $announcementId,
-                Locale::getPrimaryLocale()
-            );
-        }
 
-        if (isset($userIdsToNotifyAndMail)) {
-            foreach ($userIdsToNotifyAndMail->chunk(Mailer::BULK_EMAIL_SIZE_LIMIT) as $notifyAndMailUserIds) {
-                $jobs[] = new NewAnnouncementNotifyUsers(
-                    $notifyAndMailUserIds,
-                    $contextId,
-                    $announcementId,
-                    Locale::getPrimaryLocale(),
-                    $sender
-                );
-            }
+        if ($context) {
+            $this->notifyUsers($request, $context, $announcementId, $sendEmail);
         }
 
-        Bus::batch($jobs)->dispatch();
-
         return $response->withJson(Repo::announcement()->getSchemaMap()->map($announcement), 200);
     }
 
@@ -283,7 +243,7 @@ public function edit($slimRequest, $response, $args)
         }
 
         // Don't allow to edit an announcement from one context from a different context's endpoint
-        if ($request->getContext()->getId() !== $announcement->getData('assocId')) {
+        if ($this->getContextId() !== $announcement->getData('assocId')) {
             return $response->withStatus(403)->withJsonError('api.announcements.400.contextsNotMatched');
         }
 
@@ -292,8 +252,8 @@ public function edit($slimRequest, $response, $args)
         $params['typeId'] ??= null;
 
         $context = $request->getContext();
-        $primaryLocale = $context->getPrimaryLocale();
-        $allowedLocales = $context->getSupportedFormLocales();
+        $primaryLocale = $context ? $context->getPrimaryLocale() : $request->getSite()->getPrimaryLocale();
+        $allowedLocales = $context ? $context->getSupportedFormLocales() : $request->getSite()->getSupportedLocales();
 
         $errors = Repo::announcement()->validate($announcement, $params, $allowedLocales, $primaryLocale);
         if (!empty($errors)) {
@@ -331,7 +291,7 @@ public function delete($slimRequest, $response, $args)
         }
 
         // Don't allow to delete an announcement from one context from a different context's endpoint
-        if ($request->getContext()->getId() !== $announcement->getData('assocId')) {
+        if ($this->getContextId() !== $announcement->getData('assocId')) {
             return $response->withStatus(403)->withJsonError('api.announcements.400.contextsNotMatched');
         }
 
@@ -341,4 +301,87 @@ public function delete($slimRequest, $response, $args)
 
         return $response->withJson($announcementProps, 200);
     }
+
+    /**
+     * Get the context id or site-wide context id of the current request
+     */
+    protected function getContextId(): int
+    {
+        $context = $this->getRequest()->getContext();
+        return $context
+            ? $context->getId()
+            : Application::CONTEXT_ID_NONE;
+    }
+
+    /**
+     * Modify the role assignments so that only
+     * site admins have access
+     */
+    protected function getSiteRoleAssignments(array $roleAssignments): array
+    {
+        $roleIds = array_keys($roleAssignments);
+        foreach ($roleIds as $roleId) {
+            if ($roleId !== Role::ROLE_ID_SITE_ADMIN) {
+                unset($roleAssignments[$roleId]);
+            }
+        }
+        return $roleAssignments;
+    }
+
+    /**
+     * Notify subscribed users
+     *
+     * This only works for context-level announcements. There is no way to
+     * determine users who have subscribed to site-level announcements.
+     *
+     * @param bool $sendEmail Whether or not the editor chose to notify users by email
+     */
+    protected function notifyUsers(Request $request, Context $context, int $announcementId, bool $sendEmail): void
+    {
+        /** @var NotificationSubscriptionSettingsDAO $notificationSubscriptionSettingsDao */
+        $notificationSubscriptionSettingsDao = DAORegistry::getDAO('NotificationSubscriptionSettingsDAO');
+
+        // Notify users
+        $userIdsToNotify = $notificationSubscriptionSettingsDao->getSubscribedUserIds(
+            [NotificationSubscriptionSettingsDAO::BLOCKED_NOTIFICATION_KEY],
+            [PKPNotification::NOTIFICATION_TYPE_NEW_ANNOUNCEMENT],
+            [$context->getId()]
+        );
+
+        if ($sendEmail) {
+            $userIdsToMail = $notificationSubscriptionSettingsDao->getSubscribedUserIds(
+                [NotificationSubscriptionSettingsDAO::BLOCKED_NOTIFICATION_KEY, NotificationSubscriptionSettingsDAO::BLOCKED_EMAIL_NOTIFICATION_KEY],
+                [PKPNotification::NOTIFICATION_TYPE_NEW_ANNOUNCEMENT],
+                [$context->getId()]
+            );
+
+            $userIdsToNotifyAndMail = $userIdsToNotify->intersect($userIdsToMail);
+            $userIdsToNotify = $userIdsToNotify->diff($userIdsToMail);
+        }
+
+        $sender = $request->getUser();
+        $jobs = [];
+        foreach ($userIdsToNotify->chunk(PKPNotification::NOTIFICATION_CHUNK_SIZE_LIMIT) as $notifyUserIds) {
+            $jobs[] = new NewAnnouncementNotifyUsers(
+                $notifyUserIds,
+                $context->getId(),
+                $announcementId,
+                Locale::getPrimaryLocale()
+            );
+        }
+
+        if (isset($userIdsToNotifyAndMail)) {
+            foreach ($userIdsToNotifyAndMail->chunk(Mailer::BULK_EMAIL_SIZE_LIMIT) as $notifyAndMailUserIds) {
+                $jobs[] = new NewAnnouncementNotifyUsers(
+                    $notifyAndMailUserIds,
+                    $context->getId(),
+                    $announcementId,
+                    Locale::getPrimaryLocale(),
+                    $sender
+                );
+            }
+        }
+
+        Bus::batch($jobs)->dispatch();
+    }
 }
diff --git a/classes/announcement/Collector.php b/classes/announcement/Collector.php
index 4c64170f3de..c3a90e73068 100644
--- a/classes/announcement/Collector.php
+++ b/classes/announcement/Collector.php
@@ -27,6 +27,11 @@
  */
 class Collector implements CollectorInterface
 {
+    public const ORDERBY_DATE_POSTED = 'date_posted';
+    public const ORDERBY_DATE_EXPIRE = 'date_expire';
+    public const ORDER_DIR_ASC = 'ASC';
+    public const ORDER_DIR_DESC = 'DESC';
+
     public DAO $dao;
     public ?array $contextIds = null;
     public ?string $isActive = null;
@@ -34,6 +39,8 @@ class Collector implements CollectorInterface
     public ?array $typeIds = null;
     public ?int $count = null;
     public ?int $offset = null;
+    public string $orderBy = self::ORDERBY_DATE_POSTED;
+    public string $orderDirection = self::ORDER_DIR_DESC;
 
     public function __construct(DAO $dao)
     {
@@ -124,6 +131,21 @@ public function offset(?int $offset): self
         return $this;
     }
 
+    /**
+     * Order the results
+     *
+     * Results are ordered by the date posted by default.
+     *
+     * @param string $sorter One of the self::ORDERBY_ constants
+     * @param string $direction One of the self::ORDER_DIR_ constants
+     */
+    public function orderBy(?string $sorter, string $direction = self::ORDER_DIR_DESC): self
+    {
+        $this->orderBy = $sorter;
+        $this->orderDirection = $direction;
+        return $this;
+    }
+
     /**
      * @copydoc CollectorInterface::getQueryBuilder()
      */
@@ -180,6 +202,15 @@ public function getQueryBuilder(): Builder
             $qb->offset($this->offset);
         }
 
+        if (isset($this->orderBy)) {
+            $qb->orderBy('a.' . $this->orderBy, $this->orderDirection);
+            // Add a secondary sort by id to catch cases where two
+            // announcements share the same date
+            if (in_array($this->orderBy, [SELF::ORDERBY_DATE_EXPIRE, SELF::ORDERBY_DATE_POSTED])) {
+                $qb->orderBy('a.announcement_id', $this->orderDirection);
+            }
+        }
+
         Hook::call('Announcement::Collector', [&$qb, $this]);
 
         return $qb;
diff --git a/classes/announcement/maps/Schema.php b/classes/announcement/maps/Schema.php
index 5a336969985..e3d82f97be0 100644
--- a/classes/announcement/maps/Schema.php
+++ b/classes/announcement/maps/Schema.php
@@ -13,6 +13,8 @@
 
 namespace PKP\announcement\maps;
 
+use APP\core\Application;
+use APP\core\Request;
 use Illuminate\Support\Enumerable;
 use PKP\announcement\Announcement;
 use PKP\core\PKPApplication;
@@ -24,6 +26,12 @@ class Schema extends \PKP\core\maps\Schema
 
     public string $schema = PKPSchemaService::SCHEMA_ANNOUNCEMENT;
 
+    public function __construct(Request $request, PKPSchemaService $schemaService)
+    {
+        $this->request = $request;
+        $this->schemaService = $schemaService;
+    }
+
     /**
      * Map an announcement
      *
@@ -85,7 +93,7 @@ protected function mapByProperties(array $props, Announcement $item): array
                     $output[$prop] = $this->request->getDispatcher()->url(
                         $this->request,
                         PKPApplication::ROUTE_PAGE,
-                        $this->context->getData('urlPath'),
+                        $this->getUrlPath(),
                         'announcement',
                         'view',
                         $item->getId()
@@ -97,10 +105,26 @@ protected function mapByProperties(array $props, Announcement $item): array
             }
         }
 
-        $output = $this->schemaService->addMissingMultilingualValues($this->schema, $output, $this->context->getSupportedFormLocales());
+        $output = $this->schemaService->addMissingMultilingualValues($this->schema, $output, $this->getSupportedLocales());
 
         ksort($output);
 
         return $this->withExtensions($output, $item);
     }
+
+    protected function getUrlPath(): string
+    {
+        if (isset($this->context)) {
+            return $this->context->getData('urlPath');
+        }
+        return 'index';
+    }
+
+    protected function getSupportedLocales(): array
+    {
+        if (isset($this->context)) {
+            return $this->context->getSupportedFormLocales();
+        }
+        return Application::get()->getRequest()->getSite()->getSupportedLocales();
+    }
 }
diff --git a/classes/components/forms/announcement/PKPAnnouncementForm.php b/classes/components/forms/announcement/PKPAnnouncementForm.php
index b81bff5f3f7..3cf8fba24d6 100644
--- a/classes/components/forms/announcement/PKPAnnouncementForm.php
+++ b/classes/components/forms/announcement/PKPAnnouncementForm.php
@@ -15,12 +15,15 @@
 
 namespace PKP\components\forms\announcement;
 
+use APP\core\Application;
 use PKP\announcement\AnnouncementTypeDAO;
 use PKP\components\forms\FieldOptions;
 use PKP\components\forms\FieldRichTextarea;
 use PKP\components\forms\FieldText;
 use PKP\components\forms\FormComponent;
+use PKP\context\Context;
 use PKP\db\DAORegistry;
+use PKP\site\Site;
 
 define('FORM_ANNOUNCEMENT', 'announcement');
 
@@ -32,17 +35,21 @@ class PKPAnnouncementForm extends FormComponent
     /** @copydoc FormComponent::$method */
     public $method = 'POST';
 
+    public Context|Site $context;
+
     /**
      * Constructor
      *
      * @param string $action URL to submit the form to
      * @param array $locales Supported locales
-     * @param \PKP\context\Context $announcementContext The context to get supported announcement types
      */
-    public function __construct($action, $locales, $announcementContext)
+    public function __construct($action, $locales, Context|Site $context)
     {
         $this->action = $action;
         $this->locales = $locales;
+        $this->context = $context;
+
+        $announcementTypeOptions = $this->getAnnouncementTypeOptions();
 
         $this->addField(new FieldText('title', [
             'label' => __('common.title'),
@@ -67,22 +74,11 @@ public function __construct($action, $locales, $announcementContext)
                 'description' => __('manager.announcements.form.dateExpireInstructions'),
                 'size' => 'small',
             ]));
-
-        /** @var AnnouncementTypeDAO */
-        $announcementTypeDao = DAORegistry::getDAO('AnnouncementTypeDAO');
-        $announcementTypes = $announcementTypeDao->getByContextId($announcementContext->getId());
-        $announcementOptions = [];
-        foreach ($announcementTypes as $announcementType) {
-            $announcementOptions[] = [
-                'value' => (int) $announcementType->getId(),
-                'label' => $announcementType->getLocalizedTypeName(),
-            ];
-        }
-        if (!empty($announcementOptions)) {
+        if (!empty($announcementTypeOptions)) {
             $this->addField(new FieldOptions('typeId', [
                 'label' => __('manager.announcementTypes.typeName'),
                 'type' => 'radio',
-                'options' => $announcementOptions,
+                'options' => $announcementTypeOptions,
             ]));
         }
 
@@ -96,4 +92,26 @@ public function __construct($action, $locales, $announcementContext)
             ]
         ]));
     }
+
+    protected function getAnnouncementTypeOptions(): array
+    {
+        /** @var AnnouncementTypeDAO */
+        $announcementTypeDao = DAORegistry::getDAO('AnnouncementTypeDAO');
+
+        $announcementTypes = $announcementTypeDao->getByContextId(
+            is_a($this->context, Context::class)
+                ? $this->context->getId()
+                : Application::CONTEXT_ID_NONE
+        );
+
+        $announcementTypeOptions = [];
+        foreach ($announcementTypes as $announcementType) {
+            $announcementTypeOptions[] = [
+                'value' => (int) $announcementType->getId(),
+                'label' => $announcementType->getLocalizedTypeName(),
+            ];
+        }
+
+        return $announcementTypeOptions;
+    }
 }
diff --git a/classes/components/forms/context/PKPAnnouncementSettingsForm.php b/classes/components/forms/context/PKPAnnouncementSettingsForm.php
index e2d2d853b1b..a6aa6aa376c 100644
--- a/classes/components/forms/context/PKPAnnouncementSettingsForm.php
+++ b/classes/components/forms/context/PKPAnnouncementSettingsForm.php
@@ -19,6 +19,8 @@
 use PKP\components\forms\FieldRichTextarea;
 use PKP\components\forms\FieldText;
 use PKP\components\forms\FormComponent;
+use PKP\context\Context;
+use PKP\site\Site;
 
 define('FORM_ANNOUNCEMENT_SETTINGS', 'announcementSettings');
 
@@ -35,9 +37,8 @@ class PKPAnnouncementSettingsForm extends FormComponent
      *
      * @param string $action URL to submit the form to
      * @param array $locales Supported locales
-     * @param \PKP\context\Context $context Journal or Press to change settings for
      */
-    public function __construct($action, $locales, $context)
+    public function __construct($action, $locales, Context|Site $context)
     {
         $this->action = $action;
         $this->locales = $locales;
diff --git a/classes/components/listPanels/PKPAnnouncementsListPanel.php b/classes/components/listPanels/PKPAnnouncementsListPanel.php
index 81bc9b40a3c..c0ccf41e90b 100644
--- a/classes/components/listPanels/PKPAnnouncementsListPanel.php
+++ b/classes/components/listPanels/PKPAnnouncementsListPanel.php
@@ -16,6 +16,7 @@
 namespace PKP\components\listPanels;
 
 use APP\core\Application;
+use PKP\context\Context;
 
 class PKPAnnouncementsListPanel extends ListPanel
 {
@@ -49,14 +50,23 @@ public function getConfig()
             'editAnnouncementLabel' => __('manager.announcements.edit'),
             'form' => $this->form->getConfig(),
             'itemsMax' => $this->itemsMax,
-            'urlBase' => $request->getDispatcher()->url(
-                $request,
-                Application::ROUTE_PAGE,
-                $request->getContext()->getPath(),
-                'announcement',
-                'view',
-                '__id__'
-            )
+            'urlBase' => $this->getUrlBase()
         ];
     }
+
+    protected function getUrlBase(): string
+    {
+        $request = Application::get()->getRequest();
+
+        return $request->getDispatcher()->url(
+            $request,
+            Application::ROUTE_PAGE,
+            is_a($this->form->context, Context::class)
+                ? $request->getContext()->getPath()
+                : 'index',
+            'announcement',
+            'view',
+            '__id__'
+        );
+    }
 }
diff --git a/classes/migration/upgrade/v3_5_0/I9253_SiteAnnouncements.php b/classes/migration/upgrade/v3_5_0/I9253_SiteAnnouncements.php
new file mode 100644
index 00000000000..b243db7bd26
--- /dev/null
+++ b/classes/migration/upgrade/v3_5_0/I9253_SiteAnnouncements.php
@@ -0,0 +1,56 @@
+<?php
+
+/**
+ * @file classes/migration/upgrade/v3_5_0/I9253_SiteAnnouncements.php
+ *
+ * Copyright (c) 2014-2023 Simon Fraser University
+ * Copyright (c) 2000-2023 John Willinsky
+ * Distributed under the GNU GPL v3. For full terms see the file docs/COPYING.
+ *
+ * @class I9253_SiteAnnouncements
+ */
+
+namespace PKP\migration\upgrade\v3_5_0;
+
+use APP\core\Application;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+use PKP\migration\Migration;
+
+class I9253_SiteAnnouncements extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('announcement_types', function (Blueprint $table) {
+            $table->dropForeign(['context_id']);
+        });
+    }
+
+    /**
+     * Reverse the migration.
+     */
+    public function down(): void
+    {
+        $app = Application::getName();
+
+        $contextIdColumn = 'journal_id';
+        $contextTable = 'journals';
+        if ($app === 'omp') {
+            $contextIdColumn = 'press_id';
+            $contextTable = 'presses';
+        } elseif ($app === 'ops') {
+            $contextIdColumn = 'server_id';
+            $contextTable = 'servers';
+        }
+
+        Schema::table('announcement_types', function (Blueprint $table) use ($contextIdColumn, $contextTable) {
+            $table
+                ->foreign('context_id')
+                ->references($contextIdColumn)
+                ->on($contextTable);
+        });
+    }
+}
diff --git a/classes/services/PKPNavigationMenuService.php b/classes/services/PKPNavigationMenuService.php
index 276b839a83d..8785a243931 100755
--- a/classes/services/PKPNavigationMenuService.php
+++ b/classes/services/PKPNavigationMenuService.php
@@ -166,7 +166,10 @@ public function getDisplayStatus(&$navigationMenuItem, &$navigationMenu)
         // Conditionally hide some items
         switch ($menuItemType) {
             case NavigationMenuItem::NMI_TYPE_ANNOUNCEMENTS:
-                $navigationMenuItem->setIsDisplayed($context && $context->getData('enableAnnouncements'));
+                $navigationMenuItem->setIsDisplayed(
+                    ($context && $context->getData('enableAnnouncements'))
+                    || (!$context && $request->getSite()->getData('enableAnnouncements'))
+                );
                 break;
             case NavigationMenuItem::NMI_TYPE_EDITORIAL_TEAM:
                 $navigationMenuItem->setIsDisplayed($context && $context->getLocalizedData('editorialTeam'));
diff --git a/controllers/grid/announcements/AnnouncementTypeGridHandler.php b/controllers/grid/announcements/AnnouncementTypeGridHandler.php
index 4f18fca6bac..edfea5dabdd 100644
--- a/controllers/grid/announcements/AnnouncementTypeGridHandler.php
+++ b/controllers/grid/announcements/AnnouncementTypeGridHandler.php
@@ -16,6 +16,7 @@
 
 namespace PKP\controllers\grid\announcements;
 
+use APP\core\Application;
 use APP\notification\NotificationManager;
 use PKP\announcement\AnnouncementTypeDAO;
 use PKP\controllers\grid\announcements\form\AnnouncementTypeForm;
@@ -28,6 +29,8 @@
 use PKP\linkAction\request\AjaxModal;
 use PKP\notification\PKPNotification;
 use PKP\security\authorization\ContextAccessPolicy;
+use PKP\security\authorization\PKPSiteAccessPolicy;
+use PKP\security\authorization\UserRolesRequiredPolicy;
 use PKP\security\Role;
 
 class AnnouncementTypeGridHandler extends GridHandler
@@ -57,15 +60,20 @@ public function __construct()
      */
     public function authorize($request, &$args, $roleAssignments)
     {
-        $this->addPolicy(new ContextAccessPolicy($request, $roleAssignments));
-        $context = $request->getContext();
+        $contextId = $this->getContextId();
+
+        if ($contextId === Application::CONTEXT_ID_NONE) {
+            $this->addPolicy(new PKPSiteAccessPolicy($request, null, $roleAssignments));
+        } else {
+            $this->addPolicy(new ContextAccessPolicy($request, $roleAssignments));
+        }
 
         $announcementTypeId = $request->getUserVar('announcementTypeId');
         if ($announcementTypeId) {
             // Ensure announcement type is valid and for this context
             $announcementTypeDao = DAORegistry::getDAO('AnnouncementTypeDAO'); /** @var AnnouncementTypeDAO $announcementTypeDao */
             $announcementType = $announcementTypeDao->getById($announcementTypeId);
-            if (!$announcementType || $announcementType->getContextId() != $context->getId()) {
+            if (!$announcementType || $announcementType->getContextId() != $contextId) {
                 return false;
             }
         }
@@ -125,9 +133,8 @@ public function initialize($request, $args = null)
      */
     protected function loadData($request, $filter)
     {
-        $context = $request->getContext();
         $announcementTypeDao = DAORegistry::getDAO('AnnouncementTypeDAO'); /** @var AnnouncementTypeDAO $announcementTypeDao */
-        return $announcementTypeDao->getByContextId($context->getId());
+        return $announcementTypeDao->getByContextId($this->getContextId());
     }
 
     /**
@@ -165,10 +172,7 @@ public function addAnnouncementType($args, $request)
     public function editAnnouncementType($args, $request)
     {
         $announcementTypeId = (int)$request->getUserVar('announcementTypeId');
-        $context = $request->getContext();
-        $contextId = $context->getId();
-
-        $announcementTypeForm = new AnnouncementTypeForm($contextId, $announcementTypeId);
+        $announcementTypeForm = new AnnouncementTypeForm($this->getContextId(), $announcementTypeId);
         $announcementTypeForm->initData();
 
         return new JSONMessage(true, $announcementTypeForm->fetch($request));
@@ -186,11 +190,9 @@ public function updateAnnouncementType($args, $request)
     {
         // Identify the announcement type id.
         $announcementTypeId = $request->getUserVar('announcementTypeId');
-        $context = $request->getContext();
-        $contextId = $context->getId();
 
         // Form handling.
-        $announcementTypeForm = new AnnouncementTypeForm($contextId, $announcementTypeId);
+        $announcementTypeForm = new AnnouncementTypeForm($this->getContextId(), $announcementTypeId);
         $announcementTypeForm->readInputData();
 
         if ($announcementTypeForm->validate()) {
@@ -227,10 +229,9 @@ public function updateAnnouncementType($args, $request)
     public function deleteAnnouncementType($args, $request)
     {
         $announcementTypeId = (int) $request->getUserVar('announcementTypeId');
-        $context = $request->getContext();
 
         $announcementTypeDao = DAORegistry::getDAO('AnnouncementTypeDAO'); /** @var AnnouncementTypeDAO $announcementTypeDao */
-        $announcementType = $announcementTypeDao->getById($announcementTypeId, $context->getId());
+        $announcementType = $announcementTypeDao->getById($announcementTypeId, $this->getContextId());
         if ($announcementType && $request->checkCSRF()) {
             $announcementTypeDao->deleteObject($announcementType);
 
@@ -244,4 +245,17 @@ public function deleteAnnouncementType($args, $request)
 
         return new JSONMessage(false);
     }
+
+    /**
+     * Get the id of the request context
+     *
+     * Returns CONTEXT_ID_NONE for site-level requests
+     */
+    protected function getContextId(): int
+    {
+        $request = Application::get()->getRequest();
+        return $request->getContext()
+            ? $request->getContext()->getId()
+            : Application::CONTEXT_ID_NONE;
+    }
 }
diff --git a/locale/en/manager.po b/locale/en/manager.po
index 26dfa117244..6ead5ed78c4 100644
--- a/locale/en/manager.po
+++ b/locale/en/manager.po
@@ -107,6 +107,9 @@ msgstr "Type"
 msgid "manager.announcements.form.typeIdValid"
 msgstr "Please select a valid announcement type."
 
+msgid "manager.announcements.notEnabled"
+msgstr "You must <a href=\"#announcements/announcement-settings\">enable announcements</a>."
+
 msgid "manager.announcements.noneCreated"
 msgstr "No announcements have been created."
 
diff --git a/pages/admin/AdminHandler.php b/pages/admin/AdminHandler.php
index 2f8ca3d5c67..49e44852e11 100644
--- a/pages/admin/AdminHandler.php
+++ b/pages/admin/AdminHandler.php
@@ -26,6 +26,9 @@
 use Illuminate\Support\Str;
 use PDO;
 use PKP\cache\CacheManager;
+use PKP\components\forms\announcement\PKPAnnouncementForm;
+use PKP\components\forms\context\PKPAnnouncementSettingsForm;
+use PKP\components\listPanels\PKPAnnouncementsListPanel;
 use PKP\config\Config;
 use PKP\core\JSONMessage;
 use PKP\core\PKPContainer;
@@ -181,6 +184,7 @@ public function settings($args, $request)
         $apiUrl = $dispatcher->url($request, Application::ROUTE_API, Application::CONTEXT_ID_ALL, 'site');
         $themeApiUrl = $dispatcher->url($request, Application::ROUTE_API, Application::CONTEXT_ID_ALL, 'site/theme');
         $temporaryFileApiUrl = $dispatcher->url($request, Application::ROUTE_API, Application::CONTEXT_ID_ALL, 'temporaryFiles');
+        $announcementsApiUrl = $dispatcher->url($request, Application::ROUTE_API, Application::CONTEXT_ID_ALL, 'announcements');
 
         $publicFileManager = new PublicFileManager();
         $baseUrl = $request->getBaseUrl() . '/' . $publicFileManager->getSiteFilesPath();
@@ -196,17 +200,27 @@ public function settings($args, $request)
         $siteBulkEmailsForm = new \PKP\components\forms\site\PKPSiteBulkEmailsForm($apiUrl, $site, $contexts);
         $themeForm = new \PKP\components\forms\context\PKPThemeForm($themeApiUrl, $locales);
         $siteStatisticsForm = new \PKP\components\forms\site\PKPSiteStatisticsForm($apiUrl, $locales, $site);
+        $announcementSettingsForm = new PKPAnnouncementSettingsForm($apiUrl, $locales, $site);
+        $announcementsForm = new PKPAnnouncementForm($announcementsApiUrl, $locales, $site);
+        $announcementsListPanel = $this->getAnnouncementsListPanel($announcementsApiUrl, $announcementsForm);
 
         $templateMgr = TemplateManager::getManager($request);
 
+        $templateMgr->setConstants([
+            'FORM_ANNOUNCEMENT_SETTINGS' => FORM_ANNOUNCEMENT_SETTINGS,
+        ]);
+
         $templateMgr->setState([
+            'announcementsEnabled' => (bool) $site->getData('enableAnnouncements'),
             'components' => [
+                $announcementsListPanel->id => $announcementsListPanel->getConfig(),
                 FORM_SITE_APPEARANCE => $siteAppearanceForm->getConfig(),
                 FORM_SITE_CONFIG => $siteConfigForm->getConfig(),
                 FORM_SITE_INFO => $siteInformationForm->getConfig(),
                 FORM_SITE_BULK_EMAILS => $siteBulkEmailsForm->getConfig(),
                 FORM_THEME => $themeForm->getConfig(),
                 FORM_SITE_STATISTICS => $siteStatisticsForm->getConfig(),
+                FORM_ANNOUNCEMENT_SETTINGS => $announcementSettingsForm->getConfig(),
             ],
         ]);
 
@@ -252,6 +266,7 @@ private function siteSettingsAvailability($request)
             'siteTheme',
             'siteAppearanceSetup',
             'statistics',
+            'announcements',
         ];
 
         $singleContextSite = (Services::get('context')->getCount() == 1);
@@ -694,4 +709,34 @@ public function failedJobDetails($args, $request)
 
         $templateMgr->display('admin/failedJobDetails.tpl');
     }
+
+    /**
+     * Get the list panel for site-wide announcements
+     */
+    protected function getAnnouncementsListPanel(string $apiUrl, PKPAnnouncementForm $form): PKPAnnouncementsListPanel
+    {
+        $collector = Repo::announcement()
+            ->getCollector()
+            ->filterByContextIds([Application::CONTEXT_ID_NONE]);
+
+        $itemsMax = $collector->getCount();
+        $items = Repo::announcement()->getSchemaMap()->summarizeMany(
+            $collector->limit(30)->getMany()
+        );
+
+        return new PKPAnnouncementsListPanel(
+            'announcements',
+            __('manager.setup.announcements'),
+            [
+                'apiUrl' => $apiUrl,
+                'form' => $form,
+                'getParams' => [
+                    'contextIds' => [Application::CONTEXT_ID_NONE],
+                    'count' => 30,
+                ],
+                'items' => $items->values(),
+                'itemsMax' => $itemsMax,
+            ]
+        );
+    }
 }
diff --git a/pages/announcement/AnnouncementHandler.php b/pages/announcement/AnnouncementHandler.php
index aa45debe9ea..564bd3e7cbb 100644
--- a/pages/announcement/AnnouncementHandler.php
+++ b/pages/announcement/AnnouncementHandler.php
@@ -17,6 +17,7 @@
 namespace PKP\pages\announcement;
 
 use APP\core\Application;
+use APP\core\Request;
 use APP\facades\Repo;
 use APP\handler\Handler;
 use APP\template\TemplateManager;
@@ -25,20 +26,6 @@
 
 class AnnouncementHandler extends Handler
 {
-    //
-    // Implement methods from Handler.
-    //
-    /**
-     * @copydoc Handler::authorize()
-     */
-    public function authorize($request, &$args, $roleAssignments)
-    {
-        $this->addPolicy(new ContextRequiredPolicy($request));
-
-        return parent::authorize($request, $args, $roleAssignments);
-    }
-
-
     //
     // Public handler methods.
     //
@@ -50,22 +37,19 @@ public function authorize($request, &$args, $roleAssignments)
      */
     public function index($args, $request)
     {
-        if (!$request->getContext()->getData('enableAnnouncements')) {
+        if (!$this->isAnnouncementsEnabled($request)) {
             $request->getDispatcher()->handle404();
         }
 
         $this->setupTemplate($request);
 
-        $context = $request->getContext();
-        $announcementsIntro = $context->getLocalizedData('announcementsIntroduction');
-
         $templateMgr = TemplateManager::getManager($request);
-        $templateMgr->assign('announcementsIntroduction', $announcementsIntro);
+        $templateMgr->assign('announcementsIntroduction', $this->getAnnouncementsIntro($request));
 
         // TODO the announcements list should support pagination
         $announcements = Repo::announcement()
             ->getCollector()
-            ->filterByContextIds([$context->getId()])
+            ->filterByContextIds([$this->getContextId($request)])
             ->filterByActive()
             ->getMany();
 
@@ -81,16 +65,23 @@ public function index($args, $request)
      */
     public function view($args, $request)
     {
-        if (!$request->getContext()->getData('enableAnnouncements')) {
+        if (!$this->isAnnouncementsEnabled($request)) {
             $request->getDispatcher()->handle404();
         }
         $this->validate();
         $this->setupTemplate($request);
 
-        $context = $request->getContext();
+        $contextId = $this->getContextId($request);
         $announcementId = (int) array_shift($args);
         $announcement = Repo::announcement()->get($announcementId);
-        if ($announcement && $announcement->getAssocType() == Application::getContextAssocType() && $announcement->getAssocId() == $context->getId() && ($announcement->getDateExpire() == null || strtotime($announcement->getDateExpire()) > time())) {
+        if (
+            $announcement
+            && $announcement->getAssocType() == Application::getContextAssocType()
+            && $announcement->getAssocId() == $contextId
+            && (
+                $announcement->getDateExpire() == null || strtotime($announcement->getDateExpire()) > time()
+            )
+        ) {
             $templateMgr = TemplateManager::getManager($request);
             $templateMgr->assign('announcement', $announcement);
             $templateMgr->assign('announcementTitle', $announcement->getLocalizedTitleFull());
@@ -98,4 +89,24 @@ public function view($args, $request)
         }
         $request->redirect(null, 'announcement');
     }
+
+    protected function getContextId(Request $request): int
+    {
+        $context = $request->getContext();
+        return $context
+            ? $context->getId()
+            : Application::CONTEXT_ID_NONE;
+    }
+
+    protected function isAnnouncementsEnabled(Request $request): bool
+    {
+        $contextOrSite = $request->getContext() ?? $request->getSite();
+        return $contextOrSite->getData('enableAnnouncements');
+    }
+
+    protected function getAnnouncementsIntro(Request $request): string
+    {
+        $contextOrSite = $request->getContext() ?? $request->getSite();
+        return $contextOrSite->getLocalizedData('announcementsIntroduction');
+    }
 }
diff --git a/pages/index/PKPIndexHandler.php b/pages/index/PKPIndexHandler.php
index 3f1c83a1f60..c491bc2e467 100644
--- a/pages/index/PKPIndexHandler.php
+++ b/pages/index/PKPIndexHandler.php
@@ -16,9 +16,11 @@
 
 namespace PKP\pages\index;
 
+use APP\core\Application;
 use APP\facades\Repo;
 use APP\handler\Handler;
 use PKP\context\Context;
+use PKP\site\Site;
 use PKP\template\PKPTemplateManager;
 
 class PKPIndexHandler extends Handler
@@ -31,14 +33,18 @@ class PKPIndexHandler extends Handler
      * @param Context $context
      * @param PKPTemplateManager $templateMgr
      */
-    protected function _setupAnnouncements($context, $templateMgr)
+    protected function _setupAnnouncements(Context|Site $contextOrSite, $templateMgr)
     {
-        $enableAnnouncements = $context->getData('enableAnnouncements');
-        $numAnnouncementsHomepage = $context->getData('numAnnouncementsHomepage');
+        $enableAnnouncements = $contextOrSite->getData('enableAnnouncements');
+        $numAnnouncementsHomepage = $contextOrSite->getData('numAnnouncementsHomepage');
         if ($enableAnnouncements && $numAnnouncementsHomepage) {
             $announcements = Repo::announcement()
                 ->getCollector()
-                ->filterByContextIds([$context->getId()])
+                ->filterByContextIds([
+                    is_a($contextOrSite, Context::class)
+                        ? $contextOrSite->getId()
+                        : Application::CONTEXT_ID_NONE
+                ])
                 ->filterByActive()
                 ->limit((int) $numAnnouncementsHomepage)
                 ->getMany();
diff --git a/schemas/site.json b/schemas/site.json
index d14ff6e2b0a..c1fcf6a5da5 100644
--- a/schemas/site.json
+++ b/schemas/site.json
@@ -14,6 +14,13 @@
 				"nullable"
 			]
 		},
+		"announcementsIntroduction": {
+			"type": "string",
+			"multilingual": true,
+			"validation": [
+				"nullable"
+			]
+		},
 		"contactEmail": {
 			"type": "string",
 			"multilingual": true,
@@ -36,6 +43,12 @@
 				"nullable"
 			]
 		},
+		"enableAnnouncements": {
+			"type": "boolean",
+			"validation": [
+				"nullable"
+			]
+		},
 		"enableBulkEmails": {
 			"type": "array",
 			"description": "Which hosted journals, presses or preprint servers are allowed to send bulk emails.",
@@ -99,6 +112,13 @@
 				"min:4"
 			]
 		},
+		"numAnnouncementsHomepage": {
+			"type": "integer",
+			"validation": [
+				"nullable",
+				"min:0"
+			]
+		},
 		"pageFooter": {
 			"type": "string",
 			"multilingual": true,
diff --git a/templates/admin/settings.tpl b/templates/admin/settings.tpl
index f2c2dd5bbbf..13d116f72cc 100644
--- a/templates/admin/settings.tpl
+++ b/templates/admin/settings.tpl
@@ -97,6 +97,37 @@
 			</tabs>
 		</tab>
 		{/if}
+		{if $componentAvailability['announcements']}
+		<tab id="announcements" label="{translate key="announcement.announcements"}">
+			<tabs :is-side-tabs="true" :track-history="true">
+				<tab id="announcement-settings" label="{translate key="admin.settings"}">
+					<pkp-form
+						v-bind="components.{$smarty.const.FORM_ANNOUNCEMENT_SETTINGS}"
+						@set="set"
+					></pkp-form>
+				</tab>
+				<tab id="announcement-items" label="{translate key="announcement.announcements"}">
+					<announcements-list-panel
+						v-if="announcementsEnabled"
+						v-bind="components.announcements"
+						@set="set"
+					></announcements-list-panel>
+					<p v-else>
+						{translate key="manager.announcements.notEnabled"}
+					</p>
+				</tab>
+				<tab id="announcement-types" label="{translate key="manager.announcementTypes"}">
+					<template v-if="announcementsEnabled">
+						{capture assign=announcementTypeGridUrl}{url router=\PKP\core\PKPApplication::ROUTE_COMPONENT component="grid.announcements.AnnouncementTypeGridHandler" op="fetchGrid" escape=false}{/capture}
+						{load_url_in_div id="announcementTypeGridContainer" url=$announcementTypeGridUrl inVueEl=true}
+					</template>
+					<p v-else>
+						{translate key="manager.announcements.notEnabled"}
+					</p>
+				</tab>
+			</tabs>
+		</tab>
+		{/if}
 		{if $componentAvailability['sitePlugins']}
 		<tab id="plugins" label="{translate key="common.plugins"}">
 			{capture assign=pluginGridUrl}{url router=\PKP\core\PKPApplication::ROUTE_COMPONENT component="grid.admin.plugins.AdminPluginGridHandler" op="fetchGrid" escape=false}{/capture}