diff --git a/src/target/target_kind.cc b/src/target/target_kind.cc
index dd579b5c8a09..b9d9706773f7 100644
--- a/src/target/target_kind.cc
+++ b/src/target/target_kind.cc
@@ -350,6 +350,7 @@ TVM_REGISTER_TARGET_KIND("opencl", kDLOpenCL)
 TVM_REGISTER_TARGET_KIND("metal", kDLMetal)
     .add_attr_option<Bool>("system-lib")
     .add_attr_option<Integer>("max_num_threads", Integer(256))
+    .add_attr_option<Integer>("thread_warp_size", Integer(16))
     .set_default_keys({"metal", "gpu"});
 
 TVM_REGISTER_TARGET_KIND("vulkan", kDLVulkan)