diff --git a/lib/index.ts b/lib/index.ts
index 794d91ac..788ef799 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -236,8 +236,6 @@ export default function browserExtension<T>(
           },
           rollupOptions: {
             output: {
-              // Turn off chunking
-              manualChunks: undefined,
               // Remove hashes from output filenames for consistent builds
               entryFileNames: "[name].js",
               chunkFileNames: "[name].js",
diff --git a/lib/src/build-script.ts b/lib/src/build-script.ts
index 5ce892d6..8a445698 100644
--- a/lib/src/build-script.ts
+++ b/lib/src/build-script.ts
@@ -22,6 +22,7 @@ export async function buildScript(config: BuildScriptConfig) {
         plugin &&
         (!("name" in plugin) || plugin.name !== "vite-plugin-web-extension")
     ),
+    define: config.vite.define,
     build: {
       emptyOutDir: false,
       outDir,