diff --git a/include/boost/regex/v4/match_results.hpp b/include/boost/regex/v4/match_results.hpp
index 72538fc0..0874ef6a 100644
--- a/include/boost/regex/v4/match_results.hpp
+++ b/include/boost/regex/v4/match_results.hpp
@@ -23,6 +23,8 @@
 #  include BOOST_ABI_PREFIX
 #endif
 
+#include <algorithm>               // std::swap
+
 namespace boost{
 #ifdef BOOST_MSVC
 #pragma warning(push)