diff --git a/packages/plugin-dts/src/utils.ts b/packages/plugin-dts/src/utils.ts
index 3f1b395ef..2a90cd524 100644
--- a/packages/plugin-dts/src/utils.ts
+++ b/packages/plugin-dts/src/utils.ts
@@ -243,8 +243,8 @@ export async function redirectDtsImports(
       let redirectImportPath = importPath;
 
       if (absoluteImportPath && redirect.path) {
-        const isOutsideRootdir = !absoluteImportPath.startsWith(
-          rootDir + path.sep,
+        const isOutsideRootdir = !normalize(absoluteImportPath).startsWith(
+          normalize(rootDir) + path.sep,
         );
 
         if (isOutsideRootdir) {