diff --git a/git-hooks/sanitize-commit b/git-hooks/sanitize-commit
index 6df527233f03af96c4479a8784134637421889f0..9b110e6c1c57c87b168dcb5df79b43877084d3ed 100755
--- a/git-hooks/sanitize-commit
+++ b/git-hooks/sanitize-commit
@@ -472,7 +472,7 @@ my $tsv_check;
 my $eof_check;
 my $ctlkw_check;
 my $apple_check;
-open DIFF, "git diff-tree --patience --no-commit-id --diff-filter=ACMR --src-prefix=\@old\@/ --dst-prefix=\@new\@/ --full-index -r -U100000 --cc -C -l1000 --root ".$sha1." |" or die "cannot run git: $!";
+open DIFF, "git diff-tree --patience --no-commit-id --diff-filter=ACMR --ignore-submodules --src-prefix=\@old\@/ --dst-prefix=\@new\@/ --full-index -r -U100000 --cc -C -l1000 --root ".$sha1." |" or die "cannot run git: $!";
 while (<DIFF>) {
     if (/^-/) {
         if ($mixws_check) {