diff --git a/app/forms/assessor_interface/filter_form.rb b/app/forms/assessor_interface/filter_form.rb
index 9be8172860..dedd850a85 100644
--- a/app/forms/assessor_interface/filter_form.rb
+++ b/app/forms/assessor_interface/filter_form.rb
@@ -4,12 +4,13 @@ class AssessorInterface::FilterForm
   include ActiveModel::Model
   include ActiveRecord::AttributeAssignment
 
-  attr_accessor :assessor_ids,
+  attr_accessor :action_required_by,
+                :assessor_ids,
+                :email,
                 :location,
                 :name,
                 :reference,
-                :email,
                 :statuses,
-                :submitted_at_before,
-                :submitted_at_after
+                :submitted_at_after,
+                :submitted_at_before
 end
diff --git a/app/view_objects/assessor_interface/application_forms_index_view_object.rb b/app/view_objects/assessor_interface/application_forms_index_view_object.rb
index f2fba4092f..595f6e861b 100644
--- a/app/view_objects/assessor_interface/application_forms_index_view_object.rb
+++ b/app/view_objects/assessor_interface/application_forms_index_view_object.rb
@@ -33,6 +33,12 @@ def country_filter_options
     )
   end
 
+  def action_required_by_filter_options
+    ACTION_REQUIRED_BY_OPTIONS.map do |name|
+      action_required_by_filter_entry(name)
+    end
+  end
+
   def status_filter_options
     STATUS_FILTER_OPTIONS.each_with_object({}) do |(status, substatuses), memo|
       memo[status_filter_entry(status)] = substatuses.map do |sub_status|
@@ -43,6 +49,8 @@ def status_filter_options
 
   private
 
+  ACTION_REQUIRED_BY_OPTIONS = %w[admin assessor external].freeze
+
   STATUS_FILTER_OPTIONS = {
     preliminary_check: [],
     submitted: [],
@@ -71,18 +79,8 @@ def filter_params
     (session[:filter_params] || {}).with_indifferent_access
   end
 
-  def application_forms_with_pagy
-    @application_forms_with_pagy ||=
-      pagy(
-        ::Filters::Status.apply(
-          scope: application_forms_without_status_filter,
-          params: filter_params,
-        ).order(submitted_at: :asc),
-      )
-  end
-
-  def application_forms_without_status_filter
-    @application_forms_without_status_filter ||=
+  def application_forms_without_action_required_by_filter
+    @application_forms_without_action_required_by_filter ||=
       begin
         filters = [
           ::Filters::Assessor,
@@ -98,6 +96,39 @@ def application_forms_without_status_filter
       end
   end
 
+  def application_forms_without_status_filter
+    @application_forms_without_status_filter ||=
+      ::Filters::ActionRequiredBy.apply(
+        scope: application_forms_without_action_required_by_filter,
+        params: filter_params,
+      )
+  end
+
+  def application_forms_with_pagy
+    @application_forms_with_pagy ||=
+      pagy(
+        ::Filters::Status.apply(
+          scope: application_forms_without_status_filter,
+          params: filter_params,
+        ).order(submitted_at: :asc),
+      )
+  end
+
+  def action_required_by_filter_counts
+    @action_required_by_filter_counts ||=
+      application_forms_without_action_required_by_filter.group(
+        :action_required_by,
+      ).count
+  end
+
+  def action_required_by_filter_entry(name)
+    OpenStruct.new(
+      id: name,
+      label:
+        "#{name.humanize} (#{action_required_by_filter_counts.fetch(name, 0)})",
+    )
+  end
+
   def status_filter_counts
     @status_filter_counts ||=
       begin
diff --git a/app/views/assessor_interface/application_forms/index.html.erb b/app/views/assessor_interface/application_forms/index.html.erb
index 10b918ed3c..8034d3d1da 100644
--- a/app/views/assessor_interface/application_forms/index.html.erb
+++ b/app/views/assessor_interface/application_forms/index.html.erb
@@ -17,10 +17,10 @@
       <div class="app-checkbox-filter__container">
         <div class="app-checkbox-filter__container-inner">
           <%= f.govuk_check_boxes_fieldset :assessor_ids, legend: { size: "s" }, small: true do %>
-            <%- @view_object.assessor_filter_options.each do |option| -%>
+            <% @view_object.assessor_filter_options.each do |option| %>
               <%= f.govuk_check_box :assessor_ids, option.id, label: { text: option.name }, checked: @view_object.filter_form.assessor_ids&.include?(option.id.to_s) %>
-            <%- end -%>
-          <%- end -%>
+            <% end %>
+          <% end %>
         </div>
       </div>
     </section>
@@ -48,6 +48,14 @@
       <% end %>
     </section>
 
+    <section id="app-applications-filters-action-required-by">
+      <%= f.govuk_check_boxes_fieldset :action_required_by, legend: { size: "s" }, small: true do %>
+        <% @view_object.action_required_by_filter_options.each do |option| %>
+          <%= f.govuk_check_box :action_required_by, option.id, label: { text: option.label }, checked: @view_object.filter_form.action_required_by&.include?(option.id) %>
+        <% end %>
+      <% end %>
+    </section>
+
     <section id="app-applications-filters-status">
       <%= f.govuk_check_boxes_fieldset :statuses, legend: { size: "s" }, small: true do %>
         <% @view_object.status_filter_options.each do |option, suboptions| %>
@@ -67,7 +75,7 @@
         <% end %>
       <% end %>
     </section>
-  <%- end -%>
+  <% end %>
 </div>
 
 <div class="govuk-grid-column-two-thirds">
diff --git a/config/locales/components.en.yml b/config/locales/components.en.yml
index 4091fa04e2..399f9249f9 100644
--- a/config/locales/components.en.yml
+++ b/config/locales/components.en.yml
@@ -38,7 +38,7 @@ en:
 
     timeline_entry:
       title:
-        action_required_by_changed: Workflow changed
+        action_required_by_changed: Action required by changed
         assessor_assigned: Assessor assigned
         reviewer_assigned: Reviewer assigned
         state_changed: Status changed
diff --git a/config/locales/helpers.en.yml b/config/locales/helpers.en.yml
index 16f13346c2..d39d438eb2 100644
--- a/config/locales/helpers.en.yml
+++ b/config/locales/helpers.en.yml
@@ -101,10 +101,10 @@ en:
       assessor_interface_create_note_form:
         text: Add a note to this application
       assessor_interface_filter_form:
+        email: Applicant email
         location: Country trained in
         name: Applicant name
         reference: Application reference number
-        email: Applicant email
       assessor_interface_professional_standing_request_location_form:
         received_options:
           true: "Yes"
@@ -277,6 +277,7 @@ en:
         scotland_full_registration: Does the applicant have or are they eligible for full registration?
         school_details_cannot_be_verified_work_history_checked: Choose the schools that need reference details to be amended
       assessor_interface_filter_form:
+        action_required_by: Action required by
         assessor_ids: Assessor name
         states: Status of application
         submitted_at: Created date
diff --git a/spec/support/autoload/page_objects/assessor_interface/applications.rb b/spec/support/autoload/page_objects/assessor_interface/applications.rb
index 5677589240..a45c7b8491 100644
--- a/spec/support/autoload/page_objects/assessor_interface/applications.rb
+++ b/spec/support/autoload/page_objects/assessor_interface/applications.rb
@@ -40,6 +40,11 @@ class Applications < SitePrism::Page
                 "#assessor_interface_filter_form_submitted_at_before_1i"
       end
 
+      section :action_required_by_filter,
+              "#app-applications-filters-action-required-by" do
+        sections :items, GovukCheckboxItem, ".govuk-checkboxes__item"
+      end
+
       section :status_filter, "#app-applications-filters-status" do
         sections :statuses, GovukCheckboxItem, ".govuk-checkboxes__item"
       end
diff --git a/spec/system/assessor_interface/filtering_application_forms_spec.rb b/spec/system/assessor_interface/filtering_application_forms_spec.rb
index 05f70e14d9..2710466191 100644
--- a/spec/system/assessor_interface/filtering_application_forms_spec.rb
+++ b/spec/system/assessor_interface/filtering_application_forms_spec.rb
@@ -36,6 +36,10 @@
     and_i_apply_the_submitted_at_filter
     then_i_see_a_list_of_applications_filtered_by_submitted_at
 
+    when_i_clear_the_filters
+    and_i_apply_the_action_required_by_filter
+    then_i_see_a_list_of_applications_filtered_by_action_required_by
+
     when_i_clear_the_filters
     and_i_apply_the_status_filter
     then_i_see_a_list_of_applications_filtered_by_state
@@ -124,6 +128,24 @@ def then_i_see_a_list_of_applications_filtered_by_submitted_at
     expect(applications_page.search_results.first.name.text).to eq("John Smith")
   end
 
+  def and_i_apply_the_action_required_by_filter
+    admin_action_item =
+      applications_page.action_required_by_filter.items.find do |item|
+        item.label.text == "Admin (1)"
+      rescue Capybara::ElementNotFound
+        false
+      end
+    admin_action_item.checkbox.click
+    applications_page.apply_filters.click
+  end
+
+  def then_i_see_a_list_of_applications_filtered_by_action_required_by
+    expect(applications_page.search_results.count).to eq(1)
+    expect(applications_page.search_results.first.name.text).to eq(
+      "Emma Dubois",
+    )
+  end
+
   def and_i_apply_the_status_filter
     awarded_state =
       applications_page.status_filter.statuses.find do |status|
@@ -155,6 +177,7 @@ def application_forms
       create(
         :application_form,
         :submitted,
+        :action_required_by_admin,
         region: create(:region, country: create(:country, code: "FR")),
         given_names: "Emma",
         family_name: "Dubois",
@@ -165,6 +188,7 @@ def application_forms
       create(
         :application_form,
         :submitted,
+        :action_required_by_assessor,
         region: create(:region, country: create(:country, code: "ES")),
         given_names: "Arnold",
         family_name: "Drummond",