diff --git a/lib/std/crypto/blake3.zig b/lib/std/crypto/blake3.zig
index 0fa59a4d56edcd70871780a1021d26b46209856b..7d2e0b191d0b76ff3d6a49463ed48b6c00c6aea2 100644
--- a/lib/std/crypto/blake3.zig
+++ b/lib/std/crypto/blake3.zig
@@ -1515,6 +1515,8 @@ test "BLAKE3 reference test cases" {
 }
 
 test "BLAKE3 parallel vs sequential" {
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
     const io = std.testing.io;