diff --git a/test/algorithm/transformation2.cpp b/test/algorithm/transformation2.cpp
index 31d34ca..87249ae 100644
--- a/test/algorithm/transformation2.cpp
+++ b/test/algorithm/transformation2.cpp
@@ -6,6 +6,7 @@
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 ==============================================================================*/
 
+#include <functional>
 #include <boost/phoenix/core.hpp>
 #include <boost/phoenix/stl/algorithm/transformation.hpp>
 #include <boost/detail/lightweight_test.hpp>
diff --git a/test/algorithm/transformation3.cpp b/test/algorithm/transformation3.cpp
index 5cd4526..8a17874 100644
--- a/test/algorithm/transformation3.cpp
+++ b/test/algorithm/transformation3.cpp
@@ -6,6 +6,7 @@
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 ==============================================================================*/
 
+#include <functional>
 #include <boost/phoenix/core.hpp>
 #include <boost/phoenix/stl/algorithm/transformation.hpp>
 #include <boost/detail/lightweight_test.hpp>