diff --git a/.changeset/dirty-bags-double.md b/.changeset/dirty-bags-double.md
new file mode 100644
index 000000000000..9c5f3e99302e
--- /dev/null
+++ b/.changeset/dirty-bags-double.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes an issue with cssesc in dev mode when setting `vite.ssr.noExternal: true`
diff --git a/packages/astro/src/core/create-vite.ts b/packages/astro/src/core/create-vite.ts
index f3174b5d325c..87574eda2d18 100644
--- a/packages/astro/src/core/create-vite.ts
+++ b/packages/astro/src/core/create-vite.ts
@@ -71,6 +71,8 @@ const ONLY_DEV_EXTERNAL = [
 	'prismjs/components/index.js',
 	// Imported by `astro/assets` -> `packages/astro/src/core/logger/core.ts`
 	'string-width',
+	// Imported by `astro:transitions` -> packages/astro/src/runtime/server/transition.ts
+	'cssesc',
 ];
 
 /** Return a base vite config as a common starting point for all Vite commands. */