diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb2f3f0..f987316 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- Support for async uploads with `Client::uploadAsync()`;
+
 ## [3.3.1] - 2024-07-23
 
 ### Changed
diff --git a/README.md b/README.md
index 245bbcb..6414c9e 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,9 @@ The checksum can be disabled using the `$withChecksum` parameter:
 $client->upload('/path/to/local/file.txt', 'remote/path/hello-world.txt', false);
 ```
 
+> [!NOTE]
+> Async uploads are supported with `$client->uploadAsync()`. It will return a `GuzzleHttp\Promise\PromiseInterface`.
+
 ---
 
 ### Downloading objects
diff --git a/src/Client.php b/src/Client.php
index 892e281..c8e24bc 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -5,6 +5,7 @@
 namespace Bunny\Storage;
 
 use GuzzleHttp\Client as HttpClient;
+use GuzzleHttp\Promise\PromiseInterface;
 use GuzzleHttp\Promise\Utils as PromiseUtils;
 use Psr\Http\Message\ResponseInterface;
 
@@ -92,10 +93,22 @@ public function putContents(string $path, string $contents, bool $withChecksum =
             $headers['Checksum'] = strtoupper(hash('sha256', $contents));
         }
 
-        $this->makeUploadRequest($path, ['headers' => $headers, 'body' => $contents]);
+        $promise = $this->makeUploadRequest($path, ['headers' => $headers, 'body' => $contents]);
+        $promise->wait();
     }
 
     public function upload(string $localPath, string $path, bool $withChecksum = true): void
+    {
+        $promise = $this->uploadWithOptions($localPath, $path, $withChecksum);
+        $promise->wait();
+    }
+
+    public function uploadAsync(string $localPath, string $path, bool $withChecksum = true): PromiseInterface
+    {
+        return $this->uploadWithOptions($localPath, $path, $withChecksum);
+    }
+
+    private function uploadWithOptions(string $localPath, string $path, bool $withChecksum): PromiseInterface
     {
         $fileStream = fopen($localPath, 'r');
         if (false === $fileStream) {
@@ -110,37 +123,31 @@ public function upload(string $localPath, string $path, bool $withChecksum = tru
             }
         }
 
-        $this->makeUploadRequest($path, ['headers' => $headers, 'body' => $fileStream]);
+        return $this->makeUploadRequest($path, ['headers' => $headers, 'body' => $fileStream]);
     }
 
     /**
      * @param array{headers: array<array-key, mixed>, body: mixed} $options
      */
-    private function makeUploadRequest(string $path, array $options): void
+    private function makeUploadRequest(string $path, array $options): PromiseInterface
     {
-        $response = $this->httpClient->request('PUT', $this->normalizePath($path), $options);
-
-        if (401 === $response->getStatusCode()) {
-            throw new AuthenticationException($this->storageZoneName, $this->apiAccessKey);
-        }
+        $response = $this->httpClient->requestAsync('PUT', $this->normalizePath($path), $options);
 
-        if (400 === $response->getStatusCode()) {
-            /** @var bool|array{Message: string}|null $json */
-            $json = json_decode($response->getBody()->getContents(), true);
-            $message = 'Checksum and file contents mismatched';
-
-            if (isset($json['Message']) && is_array($json) && is_string($json['Message'])) {
-                $message = (string) $json['Message'];
+        return $response->then(function (ResponseInterface $response) {
+            if (401 === $response->getStatusCode()) {
+                throw new AuthenticationException($this->storageZoneName, $this->apiAccessKey);
             }
 
-            throw new Exception($message);
-        }
+            if (400 === $response->getStatusCode()) {
+                throw new Exception('Checksum and file contents mismatched');
+            }
 
-        if (201 === $response->getStatusCode()) {
-            return;
-        }
+            if (201 === $response->getStatusCode()) {
+                return;
+            }
 
-        throw new Exception('Could not upload file');
+            throw new Exception('Could not upload file');
+        });
     }
 
     public function getContents(string $path): string
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index ba7b131..5d87435 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -41,34 +41,37 @@ public static function deleteDataProvider(): array
      */
     public function testUpload(string $file, bool $withChecksum, ?string $expectedChecksum)
     {
-        $options = function (array $options) use ($expectedChecksum): bool {
-            if (!is_resource($options['body'])) {
-                return false;
-            }
+        $thenPromise = $this->createMock(\GuzzleHttp\Promise\Promise::class);
+        $thenPromise->expects($this->once())->method('wait');
 
-            if (null === $expectedChecksum) {
-                return !isset($options['headers']['Checksum']);
-            }
+        $httpPromise = $this->createMock(\GuzzleHttp\Promise\Promise::class);
+        $httpPromise->expects($this->once())->method('then')->willReturn($thenPromise);
 
-            if (!isset($options['headers']['Checksum'])) {
-                return false;
-            }
+        $httpClient = $this->createMock(\GuzzleHttp\Client::class);
+        $httpClient->expects($this->once())->method('requestAsync')->with('PUT', 'test/'.$file, $this->callback($this->uploadOptionsCallback($expectedChecksum)))->willReturn($httpPromise);
 
-            if ($expectedChecksum !== $options['headers']['Checksum']) {
-                return false;
-            }
+        $client = new Client('abc1234d', 'test', Region::FALKENSTEIN, $httpClient);
+        $client->upload(__DIR__.'/_files/'.$file, $file, $withChecksum);
+    }
 
-            return true;
-        };
+    /**
+     * @dataProvider uploadDataProvider
+     */
+    public function testUploadAsync(string $file, bool $withChecksum, ?string $expectedChecksum)
+    {
+        $thenPromise = $this->createMock(\GuzzleHttp\Promise\Promise::class);
+        $thenPromise->expects($this->never())->method('wait');
 
-        $response = $this->createMock(\Psr\Http\Message\ResponseInterface::class);
-        $response->expects($this->atLeastOnce())->method('getStatusCode')->willReturn(201);
+        $httpPromise = $this->createMock(\GuzzleHttp\Promise\Promise::class);
+        $httpPromise->expects($this->once())->method('then')->willReturn($thenPromise);
 
         $httpClient = $this->createMock(\GuzzleHttp\Client::class);
-        $httpClient->expects($this->once())->method('request')->with('PUT', 'test/'.$file, $this->callback($options))->willReturn($response);
+        $httpClient->expects($this->once())->method('requestAsync')->with('PUT', 'test/'.$file, $this->callback($this->uploadOptionsCallback($expectedChecksum)))->willReturn($httpPromise);
 
         $client = new Client('abc1234d', 'test', Region::FALKENSTEIN, $httpClient);
-        $client->upload(__DIR__.'/_files/'.$file, $file, $withChecksum);
+        $result = $client->uploadAsync(__DIR__.'/_files/'.$file, $file, $withChecksum);
+
+        $this->assertSame($thenPromise, $result);
     }
 
     public static function uploadDataProvider(): array
@@ -146,4 +149,27 @@ public static function infoDatesDataProvider(): array
             [true, '', '', '01/02/03 04:05:06', '01/02/03 04:05:06'],
         ];
     }
+
+    private function uploadOptionsCallback(?string $expectedChecksum)
+    {
+        return function (array $options) use ($expectedChecksum): bool {
+            if (!is_resource($options['body'])) {
+                return false;
+            }
+
+            if (null === $expectedChecksum) {
+                return !isset($options['headers']['Checksum']);
+            }
+
+            if (!isset($options['headers']['Checksum'])) {
+                return false;
+            }
+
+            if ($expectedChecksum !== $options['headers']['Checksum']) {
+                return false;
+            }
+
+            return true;
+        };
+    }
 }