diff --git a/packages/next/src/build/webpack/plugins/next-types-plugin.ts b/packages/next/src/build/webpack/plugins/next-types-plugin.ts
index fe794b60cb7e1..1bcb85d0c95a5 100644
--- a/packages/next/src/build/webpack/plugins/next-types-plugin.ts
+++ b/packages/next/src/build/webpack/plugins/next-types-plugin.ts
@@ -220,15 +220,23 @@ export class NextTypesPlugin {
       return
     }
 
+    // Filter out non-page files in pages dir
+    if (
+      !isApp &&
+      /[/\\](?:_app|_document|_error|404|500)\.[^.]+$/.test(filePath)
+    ) {
+      return
+    }
+
     const page = isApp
       ? normalizeAppPath(path.relative(this.appDir, filePath))
       : '/' + path.relative(this.pagesDir, filePath)
 
     let route =
       (isApp
-        ? page.replace(/\/page\.[^./]+$/, '')
-        : page.replace(/\.[^./]+$/, '')
-      ).replace(/\/index$/, '') || '/'
+        ? page.replace(/[/\\]page\.[^./]+$/, '')
+        : page.replace(/\.[^./]+$/, '').replace(/[/\\]index$/, '')
+      ).replace(/\\/g, '/') || '/'
 
     if (isDynamicRoute(route)) {
       route = route