diff --git a/src/utils.ts b/src/utils.ts
index 354a8e7..2a236fb 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -33,7 +33,7 @@ export function normalizeid (id: string): string {
   if (BUILTIN_MODULES.has(id)) {
     return 'node:' + id
   }
-  return 'file://' + normalizeSlash(id)
+  return 'file://' + normalizeSlash(encodeURI(id))
 }
 
 export async function loadURL (url: string): Promise<string> {