diff --git a/packages/next-mdx/readme.md b/packages/next-mdx/readme.md
index ca7656bb886ac..2378f35272b41 100644
--- a/packages/next-mdx/readme.md
+++ b/packages/next-mdx/readme.md
@@ -61,7 +61,7 @@ module.exports = withMDX()
 
 ## Top level .mdx pages
 
-Define the `pagesExtensions` option to have Next.js handle `.mdx` files in the `pages` directory as pages:
+Define the `pageExtensions` option to have Next.js handle `.mdx` files in the `pages` directory as pages:
 
 ```js
 // next.config.js