diff --git a/nixos/lib/make-iso9660-image.nix b/nixos/lib/make-iso9660-image.nix
index 2c3026875c0e..0f3f2b5b5234 100644
--- a/nixos/lib/make-iso9660-image.nix
+++ b/nixos/lib/make-iso9660-image.nix
@@ -12,7 +12,7 @@
 , # In addition to `contents', the closure of the store paths listed
   # in `storeContents' are also placed in the Nix store of the CD.
   # This is a list of attribute sets {object, symlink} where `object'
-  # if a store path whose closure will be copied, and `symlink' is a
+  # is a store path whose closure will be copied, and `symlink' is a
   # symlink to `object' that will be added to the CD.
   storeContents ? []