diff --git a/include/boost/algorithm/minmax.hpp b/include/boost/algorithm/minmax.hpp
index 1690f14..2b5101a 100644
--- a/include/boost/algorithm/minmax.hpp
+++ b/include/boost/algorithm/minmax.hpp
@@ -26,6 +26,7 @@
  */
 
 #include <boost/tuple/tuple.hpp> // for using pairs with boost::cref
+#include <boost/ref.hpp>
 
 namespace boost {