diff --git a/packages/vidstack/src/providers/vimeo/utils.test.ts b/packages/vidstack/src/providers/vimeo/utils.test.ts
new file mode 100644
index 000000000..1392d5c45
--- /dev/null
+++ b/packages/vidstack/src/providers/vimeo/utils.test.ts
@@ -0,0 +1,88 @@
+import { vi } from 'vitest';
+
+import type { VimeoOEmbedData } from './embed/misc';
+import { getVimeoVideoInfo } from './utils';
+
+it('preserves the aspect ratio for landscape Vimeo posters', async () => {
+  mockOEmbed(
+    createOEmbedData({
+      width: 1920,
+      height: 1080,
+      thumbnail_url: 'https://i.vimeocdn.com/video/123456789_640.jpg',
+    }),
+  );
+
+  const info = (await getVimeoVideoInfo('123', new AbortController()))!;
+
+  expect(info.poster).to.equal('https://i.vimeocdn.com/video/123456789_1920x1080.webp');
+});
+
+it('preserves the aspect ratio for portrait Vimeo posters', async () => {
+  mockOEmbed(
+    createOEmbedData({
+      width: 1080,
+      height: 1920,
+      thumbnail_url: 'https://i.vimeocdn.com/video/987654321_640.jpg',
+    }),
+  );
+
+  const info = (await getVimeoVideoInfo('456', new AbortController()))!;
+
+  expect(info.poster).to.equal('https://i.vimeocdn.com/video/987654321_1080x1920.webp');
+});
+
+it('falls back to the original thumbnail when dimensions are missing', async () => {
+  const thumbnailUrl = 'https://i.vimeocdn.com/video/555555555_640.jpg';
+
+  mockOEmbed(
+    createOEmbedData({
+      width: 0,
+      height: 0,
+      thumbnail_width: 0,
+      thumbnail_height: 0,
+      thumbnail_url: thumbnailUrl,
+    }),
+  );
+
+  const info = (await getVimeoVideoInfo('789', new AbortController()))!;
+
+  expect(info.poster).to.equal(thumbnailUrl);
+});
+
+function mockOEmbed(data: VimeoOEmbedData) {
+  Object.defineProperty(window, 'fetch', {
+    configurable: true,
+    value: vi.fn(() =>
+      Promise.resolve({
+        json: () => Promise.resolve(data),
+      }),
+    ),
+  });
+}
+
+function createOEmbedData(overrides: Partial<VimeoOEmbedData>): VimeoOEmbedData {
+  return {
+    account_type: 'basic',
+    author_name: '',
+    author_url: '',
+    description: '',
+    duration: 0,
+    height: 1080,
+    html: '',
+    is_plus: '0',
+    provider_name: 'Vimeo',
+    provider_url: 'https://vimeo.com/',
+    thumbnail_height: 1080,
+    thumbnail_url_with_play_button: '',
+    thumbnail_url: 'https://i.vimeocdn.com/video/123456789_640.jpg',
+    thumbnail_width: 1920,
+    title: '',
+    type: 'video',
+    upload_date: '',
+    uri: '',
+    version: '1.0',
+    video_id: 0,
+    width: 1920,
+    ...overrides,
+  };
+}
diff --git a/packages/vidstack/src/providers/vimeo/utils.ts b/packages/vidstack/src/providers/vimeo/utils.ts
index 488cab8dc..c0866bea4 100644
--- a/packages/vidstack/src/providers/vimeo/utils.ts
+++ b/packages/vidstack/src/providers/vimeo/utils.ts
@@ -7,6 +7,8 @@ const infoCache = new Map<string, VimeoVideoInfo>();
 
 const pendingFetch = new Map<string, Promise<VimeoVideoInfo>>();
 
+const posterMaxSize = 1920;
+
 export function resolveVimeoVideoId(src: string) {
   const matches = src.match(videoIdRE);
   return { videoId: matches?.[1], hash: matches?.[2] };
@@ -33,15 +35,12 @@ export async function getVimeoVideoInfo(
     })
     .then((response) => response.json())
     .then((data: VimeoOEmbedData) => {
-      const thumnailRegex = /vimeocdn.com\/video\/(.*)?_/,
-        thumbnailId = data?.thumbnail_url?.match(thumnailRegex)?.[1],
-        poster = thumbnailId ? `https://i.vimeocdn.com/video/${thumbnailId}_1920x1080.webp` : '',
-        info = {
-          title: data?.title ?? '',
-          duration: data?.duration ?? 0,
-          poster,
-          pro: data.account_type !== 'basic',
-        };
+      const info = {
+        title: data?.title ?? '',
+        duration: data?.duration ?? 0,
+        poster: resolveVimeoPoster(data),
+        pro: data.account_type !== 'basic',
+      };
 
       infoCache.set(videoId, info);
       return info;
@@ -51,3 +50,35 @@ export async function getVimeoVideoInfo(
   pendingFetch.set(videoId, promise);
   return promise;
 }
+
+function resolveVimeoPoster(data: VimeoOEmbedData) {
+  const thumbnailUrl = data?.thumbnail_url ?? '',
+    thumbnailId = thumbnailUrl.match(/vimeocdn\.com\/video\/([^_/?#]+)_/)?.[1];
+
+  if (!thumbnailId) return thumbnailUrl;
+
+  const dimensions = resolvePosterDimensions(data);
+
+  return dimensions
+    ? `https://i.vimeocdn.com/video/${thumbnailId}_${dimensions.width}x${dimensions.height}.webp`
+    : thumbnailUrl;
+}
+
+function resolvePosterDimensions(data: VimeoOEmbedData) {
+  const width = data.width || data.thumbnail_width,
+    height = data.height || data.thumbnail_height;
+
+  if (!width || !height) return null;
+
+  if (width > height) {
+    return {
+      width: posterMaxSize,
+      height: Math.round((posterMaxSize * height) / width),
+    };
+  }
+
+  return {
+    width: Math.round((posterMaxSize * width) / height),
+    height: posterMaxSize,
+  };
+}