diff --git a/app/Services/Social/FacebookPublisher.php b/app/Services/Social/FacebookPublisher.php
index 0a64cec4..6f351b9f 100644
--- a/app/Services/Social/FacebookPublisher.php
+++ b/app/Services/Social/FacebookPublisher.php
@@ -4,7 +4,9 @@
 
 namespace App\Services\Social;
 
+use App\DataTransferObjects\MediaItem;
 use App\Enums\PostPlatform\ContentType;
+use App\Enums\SocialAccount\Platform;
 use App\Exceptions\Social\ErrorCategory;
 use App\Exceptions\Social\FacebookPublishException;
 use App\Exceptions\Social\SocialPublishException;
@@ -134,6 +136,10 @@ private function publishSingleImagePost(string $pageId, string $accessToken, ?st
             $payload['message'] = $content;
         }
 
+        if ($alt = $this->altFor($media)) {
+            $payload['alt_text_custom'] = $alt;
+        }
+
         $response = $this->facebookHttp()->post("{$this->baseUrl}/{$pageId}/photos", $payload);
 
         if ($response->failed()) {
@@ -163,11 +169,17 @@ private function publishMultiImagePost(string $pageId, string $accessToken, ?str
                 continue;
             }
 
-            $uploadResponse = $this->facebookHttp()->post("{$this->baseUrl}/{$pageId}/photos", [
+            $uploadPayload = [
                 'url' => $this->cropImageForAspectRatio($media->url, $aspectRatio),
                 'published' => 'false',
                 'access_token' => $accessToken,
-            ]);
+            ];
+
+            if ($alt = $this->altFor($media)) {
+                $uploadPayload['alt_text_custom'] = $alt;
+            }
+
+            $uploadResponse = $this->facebookHttp()->post("{$this->baseUrl}/{$pageId}/photos", $uploadPayload);
 
             if ($uploadResponse->failed()) {
                 Log::error('Facebook image upload failed', [
@@ -412,6 +424,16 @@ private function handleApiError(Response $response): never
         throw FacebookPublishException::fromApiResponse($response);
     }
 
+    /**
+     * User-provided alt text for the image, capped to Facebook's accepted length.
+     */
+    private function altFor(MediaItem $media): ?string
+    {
+        $alt = $media->altText();
+
+        return $alt === null ? null : mb_substr($alt, 0, Platform::Facebook->altTextMaxLength());
+    }
+
     protected function cropFailureException(string $message): SocialPublishException
     {
         return new FacebookPublishException(
diff --git a/tests/Feature/Services/Social/FacebookPublisherTest.php b/tests/Feature/Services/Social/FacebookPublisherTest.php
index a5e8e37e..fe711086 100644
--- a/tests/Feature/Services/Social/FacebookPublisherTest.php
+++ b/tests/Feature/Services/Social/FacebookPublisherTest.php
@@ -807,3 +807,107 @@ function facebookJpegBytes(int $width = 1200, int $height = 800): string
     Http::assertSent(fn ($request) => str_contains($request->url(), '/page_123/photos')
         && $request['url'] === 'https://example.com/media/a.jpg');
 });
+
+test('facebook publisher sends capped alt text on single image post', function () {
+    $longAlt = str_repeat('a', 1500);
+
+    $this->post->update([
+        'media' => [
+            [
+                'id' => 'test-media-id',
+                'path' => 'media/2026-01/image.jpg',
+                'url' => 'https://example.com/media/2026-01/image.jpg',
+                'mime_type' => 'image/jpeg',
+                'original_filename' => 'image.jpg',
+                'meta' => ['alt_text' => $longAlt],
+            ],
+        ],
+    ]);
+
+    Http::fake([
+        '*/page_123/photos' => Http::response(['id' => 'photo_123', 'post_id' => 'post_123'], 200),
+    ]);
+
+    $this->publisher->publish($this->postPlatform);
+
+    $expectedAlt = mb_substr($longAlt, 0, Platform::Facebook->altTextMaxLength());
+
+    Http::assertSent(function ($request) use ($expectedAlt) {
+        return str_contains($request->url(), '/page_123/photos')
+            && data_get($request->data(), 'alt_text_custom') === $expectedAlt
+            && strlen($expectedAlt) === Platform::Facebook->altTextMaxLength();
+    });
+});
+
+test('facebook publisher sends capped alt text for each image in multi image post', function () {
+    $longAlt1 = str_repeat('b', 1200);
+    $longAlt2 = str_repeat('c', 1200);
+
+    $this->post->update([
+        'media' => [
+            [
+                'id' => 'm1',
+                'path' => 'media/2026-01/image1.jpg',
+                'url' => 'https://example.com/media/2026-01/image1.jpg',
+                'mime_type' => 'image/jpeg',
+                'original_filename' => 'image1.jpg',
+                'meta' => ['alt_text' => $longAlt1],
+            ],
+            [
+                'id' => 'm2',
+                'path' => 'media/2026-01/image2.jpg',
+                'url' => 'https://example.com/media/2026-01/image2.jpg',
+                'mime_type' => 'image/jpeg',
+                'original_filename' => 'image2.jpg',
+                'meta' => ['alt_text' => $longAlt2],
+            ],
+        ],
+    ]);
+
+    Http::fake([
+        '*/page_123/photos' => Http::sequence()
+            ->push(['id' => 'photo_1'], 200)
+            ->push(['id' => 'photo_2'], 200),
+        '*/page_123/feed' => Http::response(['id' => 'multi_post_alt'], 200),
+    ]);
+
+    $this->publisher->publish($this->postPlatform);
+
+    $expectedAlt1 = mb_substr($longAlt1, 0, Platform::Facebook->altTextMaxLength());
+    $expectedAlt2 = mb_substr($longAlt2, 0, Platform::Facebook->altTextMaxLength());
+
+    Http::assertSent(function ($request) use ($expectedAlt1) {
+        return str_contains($request->url(), '/page_123/photos')
+            && data_get($request->data(), 'alt_text_custom') === $expectedAlt1;
+    });
+
+    Http::assertSent(function ($request) use ($expectedAlt2) {
+        return str_contains($request->url(), '/page_123/photos')
+            && data_get($request->data(), 'alt_text_custom') === $expectedAlt2;
+    });
+});
+
+test('facebook publisher omits alt_text_custom from photos payload when no alt text is set', function () {
+    $this->post->update([
+        'media' => [
+            [
+                'id' => 'test-media-id',
+                'path' => 'media/2026-01/image.jpg',
+                'url' => 'https://example.com/media/2026-01/image.jpg',
+                'mime_type' => 'image/jpeg',
+                'original_filename' => 'image.jpg',
+            ],
+        ],
+    ]);
+
+    Http::fake([
+        '*/page_123/photos' => Http::response(['id' => 'photo_123', 'post_id' => 'post_123'], 200),
+    ]);
+
+    $this->publisher->publish($this->postPlatform);
+
+    Http::assertSent(function ($request) {
+        return str_contains($request->url(), '/page_123/photos')
+            && ! array_key_exists('alt_text_custom', $request->data());
+    });
+});