diff --git a/packages/runtime/src/helpers/files.ts b/packages/runtime/src/helpers/files.ts
index cfbb25f353..4e747df403 100644
--- a/packages/runtime/src/helpers/files.ts
+++ b/packages/runtime/src/helpers/files.ts
@@ -353,6 +353,11 @@ export const getSourceFileForPage = (page: string, roots: string[], pageExtensio
       if (existsSync(file)) {
         return file
       }
+
+      const fileAtFolderIndex = join(root, page, `index.${extension}`)
+      if (existsSync(fileAtFolderIndex)) {
+        return fileAtFolderIndex
+      }
     }
   }
   console.log('Could not find source file for page', page)
diff --git a/test/fixtures/page-extensions/index/pages/api/index/index.js b/test/fixtures/page-extensions/index/pages/api/index/index.js
new file mode 100644
index 0000000000..172f1ae6a4
--- /dev/null
+++ b/test/fixtures/page-extensions/index/pages/api/index/index.js
@@ -0,0 +1 @@
+// noop
diff --git a/test/helpers/files.spec.ts b/test/helpers/files.spec.ts
index 02672a3958..019dd38b64 100644
--- a/test/helpers/files.spec.ts
+++ b/test/helpers/files.spec.ts
@@ -237,4 +237,13 @@ describe('getSourceFileForPage', () => {
 
     expect(filePath.replace(TEST_DIR, '')).toBe('/fixtures/page-extensions/custom/pages/api/custom.api.js')
   })
+
+  it('handles getting file when index of folder', () => {
+    const pagesDir = resolve(__dirname, '../fixtures/page-extensions/index/pages')
+    const apiRoute = '/api/index'
+
+    const filePath = getSourceFileForPage(apiRoute, [pagesDir])
+
+    expect(filePath.replace(TEST_DIR, '')).toBe('/fixtures/page-extensions/index/pages/api/index/index.js')
+  })
 })