diff --git a/test/libcxx/test/config.py b/test/libcxx/test/config.py
index 6655743ae..7db7636db 100644
--- a/test/libcxx/test/config.py
+++ b/test/libcxx/test/config.py
@@ -627,6 +627,7 @@ class Configuration(object):
                 '-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER',
                 '-Wall', '-Wextra', '-Werror'
             ]
+            self.cxx.addWarningFlagIfSupported('-Wshadow')
             self.cxx.addWarningFlagIfSupported('-Wno-unused-command-line-argument')
             self.cxx.addWarningFlagIfSupported('-Wno-attributes')
             self.cxx.addWarningFlagIfSupported('-Wno-pessimizing-move')