diff --git a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp
--- a/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp
@@ -13,6 +13,8 @@
 // explicit codecvt_byname(const char* nm, size_t refs = 0);
 // explicit codecvt_byname(const string& nm, size_t refs = 0);
 
+// REQUIRES: locale.en_US
+
 #include <locale>
 #include <cassert>
 
diff --git a/libcxx/utils/libcxx/test/features.py b/libcxx/utils/libcxx/test/features.py
--- a/libcxx/utils/libcxx/test/features.py
+++ b/libcxx/utils/libcxx/test/features.py
@@ -221,6 +221,7 @@
 # names on various systems. Each locale is considered supported if any of the
 # alternative names is supported.
 locales = {
+  'en_US':           ['en_US'],
   'en_US.UTF-8':     ['en_US.UTF-8', 'en_US.utf8', 'English_United States.1252'],
   'fr_FR.UTF-8':     ['fr_FR.UTF-8', 'fr_FR.utf8', 'French_France.1252'],
   'ja_JP.UTF-8':     ['ja_JP.UTF-8', 'ja_JP.utf8', 'Japanese_Japan.923'],