diff --git a/packages/gatsby-plugin-mdx/utils/gen-mdx.js b/packages/gatsby-plugin-mdx/utils/gen-mdx.js
index 8e51b88dee1dd..fc6fbd4b3ef3d 100644
--- a/packages/gatsby-plugin-mdx/utils/gen-mdx.js
+++ b/packages/gatsby-plugin-mdx/utils/gen-mdx.js
@@ -150,7 +150,7 @@ ${code}`
           {
             useBuiltIns: `entry`,
             corejs: 2,
-            modules: `false`,
+            modules: false,
           },
         ],
       ],