diff --git a/src/core/build/buildEntrypoints.ts b/src/core/build/buildEntrypoints.ts
index a5cef369..fcce9dc2 100644
--- a/src/core/build/buildEntrypoints.ts
+++ b/src/core/build/buildEntrypoints.ts
@@ -78,6 +78,10 @@ async function buildSingleEntrypoint(
         },
       },
     },
+    define: {
+      // See https://github.com/aklinker1/vite-plugin-web-extension/issues/96
+      'process.env.NODE_ENV': JSON.stringify(config.mode),
+    },
   };
   const entryConfig = vite.mergeConfig(
     libMode,