diff --git a/include/__config b/include/__config
index 467ab00..321e717 100644
--- a/include/__config
+++ b/include/__config
@@ -727,7 +727,8 @@
 #define _NOALIAS
 #endif
 
-#if __has_feature(cxx_explicit_conversions) || defined(__IBMCPP__)
+#if __has_feature(cxx_explicit_conversions) || defined(__IBMCPP__) || \
+    (!defined(_LIBCPP_CXX03_LANG) && defined(__GNUC__)) // All supported GCC versions
 #   define _LIBCPP_EXPLICIT explicit
 #else
 #   define _LIBCPP_EXPLICIT