diff --git a/include/boost/operators.hpp b/include/boost/operators.hpp
index 058796e..ab20330 100644
--- a/include/boost/operators.hpp
+++ b/include/boost/operators.hpp
@@ -82,11 +82,12 @@
 #ifndef BOOST_OPERATORS_HPP
 #define BOOST_OPERATORS_HPP
 
+#include <cstddef>
+#include <iterator>
+
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
 
-#include <cstddef>
-
 #if defined(__sgi) && !defined(__GNUC__)
 #   pragma set woff 1234
 #endif