diff --git a/Makefile b/Makefile
index 7c6b6f3eb..051c66a8f 100644
--- a/Makefile
+++ b/Makefile
@@ -73,7 +73,7 @@ node_modules/.installed : src/js/package.json src/js/package-lock.json
 	touch node_modules/.installed
 
 dist/pyodide.js src/js/_pyodide.out.js: src/js/*.ts src/js/pyproxy.gen.ts src/js/error_handling.gen.ts node_modules/.installed
-	npx rollup -c src/js/rollup.config.js
+	npx rollup -c src/js/rollup.config.mjs
 
 dist/package.json : src/js/package.json
 	cp $< $@
diff --git a/src/js/rollup.config.js b/src/js/rollup.config.mjs
similarity index 100%
rename from src/js/rollup.config.js
rename to src/js/rollup.config.mjs