diff --git a/src/content/docs/en/guides/actions.mdx b/src/content/docs/en/guides/actions.mdx
index 4a2fc1b1879c2..5445af3c5a86e 100644
--- a/src/content/docs/en/guides/actions.mdx
+++ b/src/content/docs/en/guides/actions.mdx
@@ -411,6 +411,8 @@ Calling [Astro.getActionResult()](/en/reference/api-reference/#getactionresult)
 
 To call an action from an HTML form, add `method="POST"` to your `<form>`, then set the form's `action` attribute using your action, for example `action={actions.logout}`. This will set the `action` attribute to use a query string that is handled by the server automatically.
 
+Note: If your form includes file uploads, you must also add `enctype="multipart/form-data"` to the `<form>` element. This ensures that files are sent in a format that allows Astro's schema validation library to correctly recognize `z.instanceof(File)` inputs.
+
 For example, this Astro component calls the `logout` action when the button is clicked and reloads the current page:
 
 ```astro title="src/components/LogoutButton.astro"