diff --git a/packages/webpack/src/config/client.js b/packages/webpack/src/config/client.js
index 42ef07d4a8..eea9bc07d3 100644
--- a/packages/webpack/src/config/client.js
+++ b/packages/webpack/src/config/client.js
@@ -30,7 +30,8 @@ export default class WebpackClientConfig extends WebpackBaseConfig {
       'process.env.VUE_ENV': JSON.stringify('client'),
       'process.browser': true,
       'process.client': true,
-      'process.server': false
+      'process.server': false,
+      'process.modern': false
     })
   }
 
diff --git a/packages/webpack/src/config/modern.js b/packages/webpack/src/config/modern.js
index 9bbcf92177..5f1af48e0e 100644
--- a/packages/webpack/src/config/modern.js
+++ b/packages/webpack/src/config/modern.js
@@ -6,6 +6,16 @@ export default class WebpackModernConfig extends WebpackClientConfig {
     super(builder, { name: 'modern', isServer: false, isModern: true })
   }
 
+  env() {
+    return Object.assign(super.env(), {
+      'process.env.VUE_ENV': JSON.stringify('client'),
+      'process.browser': true,
+      'process.client': true,
+      'process.server': false,
+      'process.modern': true
+    })
+  }
+
   getBabelOptions() {
     const options = clone(this.options.build.babel)
 
diff --git a/packages/webpack/src/config/server.js b/packages/webpack/src/config/server.js
index 72c939e8e5..3903b767eb 100644
--- a/packages/webpack/src/config/server.js
+++ b/packages/webpack/src/config/server.js
@@ -39,7 +39,8 @@ export default class WebpackServerConfig extends WebpackBaseConfig {
       'process.env.VUE_ENV': JSON.stringify('server'),
       'process.browser': false,
       'process.client': false,
-      'process.server': true
+      'process.server': true,
+      'process.modern': false
     })
   }