diff --git a/include/boost/function.hpp b/include/boost/function.hpp
index 1a5cca2..bdb2769 100644
--- a/include/boost/function.hpp
+++ b/include/boost/function.hpp
@@ -10,6 +10,8 @@
 // William Kempf, Jesse Jones and Karl Nelson were all very helpful in the
 // design of this library.
 
+#include <functional> // unary_function, binary_function
+
 #include <boost/preprocessor/iterate.hpp>
 #include <boost/detail/workaround.hpp>
 
diff --git a/include/boost/function/detail/prologue.hpp b/include/boost/function/detail/prologue.hpp
index ab2b323..1ef5f6e 100644
--- a/include/boost/function/detail/prologue.hpp
+++ b/include/boost/function/detail/prologue.hpp
@@ -11,7 +11,6 @@
 #define BOOST_FUNCTION_PROLOGUE_HPP
 #  include <cassert>
 #  include <algorithm>
-#  include <functional> // unary_function, binary_function
 #  include <boost/throw_exception.hpp>
 #  include <boost/config.hpp>
 #  include <boost/function/function_base.hpp>