diff --git a/include/boost/regex/v5/regex_traits_defaults.hpp b/include/boost/regex/v5/regex_traits_defaults.hpp
index f5136b97..4b81441f 100644
--- a/include/boost/regex/v5/regex_traits_defaults.hpp
+++ b/include/boost/regex/v5/regex_traits_defaults.hpp
@@ -29,6 +29,7 @@
 #include <cctype>
 #include <locale>
 #include <cwctype>
+#include <limits>
 
 namespace boost{ namespace BOOST_REGEX_DETAIL_NS{