diff --git a/libcxx/test/std/language.support/cmp/cmp.categories.pre/zero_type.verify.cpp b/libcxx/test/std/language.support/cmp/cmp.categories.pre/zero_type.verify.cpp
--- a/libcxx/test/std/language.support/cmp/cmp.categories.pre/zero_type.verify.cpp
+++ b/libcxx/test/std/language.support/cmp/cmp.categories.pre/zero_type.verify.cpp
@@ -10,6 +10,10 @@
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: apple-clang-9, apple-clang-10, apple-clang-11, apple-clang-12.0.0
 
+// In MSVC mode, there's a slightly different number of errors printed for
+// each of these, so it doesn't add up to the exact expected count of 18.
+// UNSUPPORTED: msvc
+
 // <compare>
 
 // Ensure we reject all cases where an argument other than a literal 0 is used
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.fail.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.fail.cpp
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.fail.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.fail.cpp
@@ -8,6 +8,10 @@
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // type_traits
 
+// MSVC mode seems to use different rules regarding enum sizes, so E1
+// doesn't cause an error.
+// UNSUPPORTED: msvc
+
 // underlying_type
 // Mandates: enum must not be an incomplete enumeration type.