diff --git a/packages/builder/src/builder.js b/packages/builder/src/builder.js
index 9196229faa..093cf14245 100644
--- a/packages/builder/src/builder.js
+++ b/packages/builder/src/builder.js
@@ -123,7 +123,7 @@ export default class Builder {
   resolvePlugins() {
     // Check plugins exist then set alias to their real path
     return Promise.all(this.plugins.map(async (p) => {
-      const ext = path.extname(p.src) ? '' : '{.+([^.]),/index.+([^.])}'
+      const ext = '{?(.+([^.])),/index.+([^.])}'
       const pluginFiles = await glob(`${p.src}${ext}`)
 
       if (!pluginFiles || pluginFiles.length === 0) {
diff --git a/test/fixtures/with-config/nuxt.config.js b/test/fixtures/with-config/nuxt.config.js
index 670c6508bf..13caab9570 100644
--- a/test/fixtures/with-config/nuxt.config.js
+++ b/test/fixtures/with-config/nuxt.config.js
@@ -37,6 +37,7 @@ export default {
   extensions: 'ts',
   plugins: [
     '~/plugins/test',
+    '~/plugins/test.plugin',
     { src: '~/plugins/only-client.js', ssr: false }
   ],
   loading: '~/components/loading',
diff --git a/test/fixtures/with-config/plugins/test.plugin.js b/test/fixtures/with-config/plugins/test.plugin.js
new file mode 100644
index 0000000000..9d36fa2f97
--- /dev/null
+++ b/test/fixtures/with-config/plugins/test.plugin.js
@@ -0,0 +1,5 @@
+if (process.client) {
+  window.__test_plugin_ext = true
+} else {
+  global.__test_plugin_ext = true
+}
diff --git a/test/unit/with-config.test.js b/test/unit/with-config.test.js
index 754ef49676..7860deab6e 100644
--- a/test/unit/with-config.test.js
+++ b/test/unit/with-config.test.js
@@ -90,6 +90,7 @@ describe('with-config', () => {
     expect(html).toContain('<h1>I have custom configurations</h1>')
 
     expect(window.__test_plugin).toBe(true)
+    expect(window.__test_plugin_ext).toBe(true)
   })
 
   test('/test/about (custom layout)', async () => {