diff --git a/doc/api/assert.md b/doc/api/assert.md
index 87672be02ecc6f..45693dd52b0324 100644
--- a/doc/api/assert.md
+++ b/doc/api/assert.md
@@ -112,7 +112,7 @@ Legacy assertion mode uses the [Abstract Equality Comparison][] in:
 
 To use legacy assertion mode:
 
-```cjs
+```mjs
 import assert from 'assert';
 ```