diff --git a/CHANGELOG.md b/CHANGELOG.md
index e1b147fae..d8d05d228 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Support TypeScript for `@plugin` and `@config` files ([#14317](https://github.com/tailwindlabs/tailwindcss/pull/14317))
 - Add `default` option to `@theme` to support overriding default theme values from plugins/JS config files ([#14327](https://github.com/tailwindlabs/tailwindcss/pull/14327))
+- Add support for `<style>` tags in Astro files to the Vite plugin ([#14340](https://github.com/tailwindlabs/tailwindcss/pull/14340))
 
 ### Fixed
 
diff --git a/integrations/utils.ts b/integrations/utils.ts
index 246f49375..ca8f3c3e0 100644
--- a/integrations/utils.ts
+++ b/integrations/utils.ts
@@ -536,32 +536,40 @@ export async function fetchStyles(port: number, path = '/'): Promise<string> {
   let index = await fetch(`http://localhost:${port}${path}`)
   let html = await index.text()
 
-  let regex = /<link rel="stylesheet" href="([a-zA-Z0-9\/_\.\?=%-]+)"/g
+  let linkRegex = /<link rel="stylesheet" href="([a-zA-Z0-9\/_\.\?=%-]+)"/gi
+  let styleRegex = /<style\b[^>]*>([\s\S]*?)<\/style>/gi
+
+  let stylesheets: string[] = []
 
   let paths: string[] = []
   let match
-  while ((match = regex.exec(html)) !== null) {
+  for (let match of html.matchAll(linkRegex)) {
     let path: string = match[1]
     if (path.startsWith('./')) {
       path = path.slice(1)
     }
     paths.push(path)
   }
-
-  let stylesheets = await Promise.all(
-    paths.map(async (path) => {
-      let css = await fetch(`http://localhost:${port}${path}`, {
-        headers: {
-          Accept: 'text/css',
-        },
-      })
-      return await css.text()
-    }),
+  stylesheets.push(
+    ...(await Promise.all(
+      paths.map(async (path) => {
+        let css = await fetch(`http://localhost:${port}${path}`, {
+          headers: {
+            Accept: 'text/css',
+          },
+        })
+        return await css.text()
+      }),
+    )),
   )
 
+  for (let match of html.matchAll(styleRegex)) {
+    stylesheets.push(match[1])
+  }
+
   return stylesheets.reduce((acc, css) => {
     return acc + '\n' + css
-  })
+  }, '')
 }
 
 async function gracefullyRemove(dir: string) {
diff --git a/integrations/vite/astro.test.ts b/integrations/vite/astro.test.ts
new file mode 100644
index 000000000..dba507176
--- /dev/null
+++ b/integrations/vite/astro.test.ts
@@ -0,0 +1,63 @@
+import { expect } from 'vitest'
+import { candidate, fetchStyles, html, json, retryAssertion, test, ts } from '../utils'
+
+test.debug(
+  'dev mode',
+  {
+    fs: {
+      'package.json': json`
+        {
+          "type": "module",
+          "dependencies": {
+            "astro": "^4.15.2",
+            "@tailwindcss/vite": "workspace:^",
+            "tailwindcss": "workspace:^"
+          }
+        }
+      `,
+      'astro.config.mjs': ts`
+        import tailwindcss from '@tailwindcss/vite'
+        import { defineConfig } from 'astro/config'
+
+        // https://astro.build/config
+        export default defineConfig({
+          vite: {
+            plugins: [tailwindcss()],
+          },
+        })
+      `,
+      'src/pages/index.astro': html`
+       <div class="underline">Hello, world!</div>
+
+        <style is:global>
+          @import 'tailwindcss';
+        </style>
+      `,
+    },
+  },
+  async ({ fs, spawn, getFreePort }) => {
+    let port = await getFreePort()
+    await spawn(`pnpm astro dev --port ${port}`)
+
+    await retryAssertion(async () => {
+      let css = await fetchStyles(port)
+      expect(css).toContain(candidate`underline`)
+    })
+
+    await fs.write(
+      'src/pages/index.astro',
+      html`
+        <div class="underline font-bold">Hello, world!</div>
+
+        <style is:global>
+          @import 'tailwindcss';
+        </style>
+      `,
+    )
+    await retryAssertion(async () => {
+      let css = await fetchStyles(port)
+      expect(css).toContain(candidate`underline`)
+      expect(css).toContain(candidate`font-bold`)
+    })
+  },
+)
diff --git a/packages/@tailwindcss-vite/src/index.ts b/packages/@tailwindcss-vite/src/index.ts
index 65d863548..8a1c60932 100644
--- a/packages/@tailwindcss-vite/src/index.ts
+++ b/packages/@tailwindcss-vite/src/index.ts
@@ -262,7 +262,10 @@ function getExtension(id: string) {
 
 function isPotentialCssRootFile(id: string) {
   let extension = getExtension(id)
-  let isCssFile = extension === 'css' || (extension === 'vue' && id.includes('&lang.css'))
+  let isCssFile =
+    extension === 'css' ||
+    (extension === 'vue' && id.includes('&lang.css')) ||
+    (extension === 'astro' && id.includes('&lang.css'))
   return isCssFile
 }