diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 94fb655b72..3ad1ed0787 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -980,9 +980,9 @@ static int packed_ref_iterator_advance(struct ref_iterator *ref_iterator)
 			continue;
 
 		while (prefix && *prefix) {
-			if (*refname < *prefix)
+			if ((unsigned char)*refname < (unsigned char)*prefix)
 				BUG("packed-refs backend yielded reference preceding its prefix");
-			else if (*refname > *prefix)
+			else if ((unsigned char)*refname > (unsigned char)*prefix)
 				return ITER_DONE;
 			prefix++;
 			refname++;
diff --git a/t/t1408-packed-refs.sh b/t/t1408-packed-refs.sh
index 41ba1f1d7f..833477f0fa 100755
--- a/t/t1408-packed-refs.sh
+++ b/t/t1408-packed-refs.sh
@@ -42,4 +42,19 @@ test_expect_success 'no error from stale entry in packed-refs' '
 	test_cmp expect actual
 '
 
+test_expect_success 'list packed refs with unicode characters' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit --no-tag A &&
+		git update-ref refs/heads/ HEAD &&
+		git update-ref refs/heads/z HEAD &&
+		git pack-refs --all &&
+		printf "%s commit\trefs/heads/z\n" $(git rev-parse HEAD) >expect &&
+		git for-each-ref refs/heads/z >actual &&
+		test_cmp expect actual
+	)
+'
+
 test_done