diff --git a/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp b/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
index 09cfc74ec190e..5a660d1829b73 100644
--- a/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
+++ b/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
@@ -8,6 +8,15 @@
 
 // UNSUPPORTED: c++98, c++03
 
+// Aligned allocations are not supported on macOS < 10.13
+// Note: use 'unsupported' instead of 'xfail' to ensure
+// we won't pass prior to c++17.
+// UNSUPPORTED: with_system_cxx_lib=macosx10.12
+// UNSUPPORTED: with_system_cxx_lib=macosx10.11
+// UNSUPPORTED: with_system_cxx_lib=macosx10.10
+// UNSUPPORTED: with_system_cxx_lib=macosx10.9
+
+
 // <memory>
 
 // template <class T>