diff --git a/.changeset/dull-deers-accept.md b/.changeset/dull-deers-accept.md
new file mode 100644
index 000000000000..d39b599bb017
--- /dev/null
+++ b/.changeset/dull-deers-accept.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Prevents the Code component from crashing if the lang isn't supported by falling back to `plaintext`.
diff --git a/packages/astro/components/Code.astro b/packages/astro/components/Code.astro
index 506a3ed3c0d1..3203d9ff5284 100644
--- a/packages/astro/components/Code.astro
+++ b/packages/astro/components/Code.astro
@@ -10,6 +10,7 @@ import type {
 	ThemeRegistration,
 	ThemeRegistrationRaw,
 } from 'shikiji';
+import { bundledLanguages } from 'shikiji/langs';
 import { getCachedHighlighter } from '../dist/core/shiki.js';
 
 interface Props {
@@ -92,7 +93,13 @@ if (typeof lang === 'object') {
 }
 
 const highlighter = await getCachedHighlighter({
-	langs: [lang],
+	langs: [
+		typeof lang === 'string'
+			? Object.keys(bundledLanguages).includes(lang)
+				? lang
+				: 'plaintext'
+			: lang,
+	],
 	theme,
 	experimentalThemes,
 	wrap,