diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index 74d1d49dbff..26fd8d0df8e 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -144,8 +144,8 @@ you will need to handle the situation manually.
         Report what is being added and removed from index.
 
 -z::
-	Only meaningful with `--stdin`; paths are separated with
-	NUL character instead of LF.
+	Only meaningful with `--stdin` or `--index-info`; paths are
+	separated with NUL character instead of LF.
 
 \--::
 	Do not interpret any more arguments as options.