diff --git a/t/t4062-diff-pickaxe.sh b/t/t4062-diff-pickaxe.sh
index 7c4903f497..1130c8019b 100755
--- a/t/t4062-diff-pickaxe.sh
+++ b/t/t4062-diff-pickaxe.sh
@@ -14,8 +14,10 @@ test_expect_success setup '
 	test_tick &&
 	git commit -m "A 4k file"
 '
+
+# OpenBSD only supports up to 255 repetitions, so repeat twice for 64*64=4096.
 test_expect_success '-G matches' '
-	git diff --name-only -G "^0{4096}$" HEAD^ >out &&
+	git diff --name-only -G "^(0{64}){64}$" HEAD^ >out &&
 	test 4096-zeroes.txt = "$(cat out)"
 '