diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp
index 01467ca9911e1..85b641322d99e 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array14.pass.cpp
@@ -15,6 +15,9 @@
 // XFAIL: apple-clang
 // XFAIL: using-built-library-before-llvm-11
 
+// AIX, z/OS, and MinGW default to -fno-sized-deallocation.
+// XFAIL: target={{.+}}-aix{{.*}}, target={{.+}}-zos{{.*}}, target={{.+}}-windows-gnu
+
 #include <new>
 #include <cstddef>
 #include <cstdlib>
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp
index fd7f2dbabdacc..ae614a1432f7d 100644
--- a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp
+++ b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete14.pass.cpp
@@ -15,6 +15,9 @@
 // XFAIL: apple-clang
 // XFAIL: using-built-library-before-llvm-11
 
+// AIX, z/OS, and MinGW default to -fno-sized-deallocation.
+// XFAIL: target={{.+}}-aix{{.*}}, target={{.+}}-zos{{.*}}, target={{.+}}-windows-gnu
+
 #include <new>
 #include <cstddef>
 #include <cstdlib>