diff --git a/playground/App.vue b/playground/App.vue
index 50f8706394e93b..3681bce493e952 100644
--- a/playground/App.vue
+++ b/playground/App.vue
@@ -3,6 +3,9 @@
   <p class="dev">
     <code>__DEV__: {{ dev }}</code>
   </p>
+  <p class="base">
+    <code>__BASE__: {{ base }}</code>
+  </p>
   <p class="node_env">
     <code>process.env.NODE_ENV: {{ env }}</code>
   </p>
@@ -42,6 +45,7 @@ import TestTransform from './TestTransform.vue'
 export default {
   data: () => ({
     dev: __DEV__,
+    base: __BASE__,
     env: process.env.NODE_ENV
   }),
   components: {
diff --git a/src/node/build/index.ts b/src/node/build/index.ts
index 67d277a9427c8e..14fca6ec452c1c 100644
--- a/src/node/build/index.ts
+++ b/src/node/build/index.ts
@@ -128,7 +128,8 @@ export async function build(options: BuildConfig = {}): Promise<BuildResult> {
       createReplacePlugin(
         {
           'process.env.NODE_ENV': '"production"',
-          __DEV__: 'false'
+          __DEV__: 'false',
+          __BASE__: JSON.stringify(publicBasePath)
         },
         sourcemap
       ),
diff --git a/src/node/server/serverPluginModuleRewrite.ts b/src/node/server/serverPluginModuleRewrite.ts
index ce11a9c5b6594b..8c42d2e5321641 100644
--- a/src/node/server/serverPluginModuleRewrite.ts
+++ b/src/node/server/serverPluginModuleRewrite.ts
@@ -56,6 +56,7 @@ export const moduleRewritePlugin: ServerPlugin = ({
     `\n<script type="module">` +
     `import "${hmrClientPublicPath}"\n` +
     `window.__DEV__ = true\n` +
+    `window.__BASE__ = '/'\n` +
     `window.process = { env: { NODE_ENV: 'development' }}\n` +
     `</script>\n`
 
diff --git a/test/test.js b/test/test.js
index 6fcd5c34b1b0dd..43674724d5d8d2 100644
--- a/test/test.js
+++ b/test/test.js
@@ -88,6 +88,7 @@ describe('vite', () => {
 
     test('env variables', async () => {
       expect(await getText('.dev')).toMatch(`__DEV__: ${!isBuild}`)
+      expect(await getText('.base')).toMatch(`__BASE__: /`)
       expect(await getText('.node_env')).toMatch(
         `process.env.NODE_ENV: ${isBuild ? 'production' : 'development'}`
       )