diff --git a/include/boost/mpl/lambda_fwd.hpp b/include/boost/mpl/lambda_fwd.hpp
index 253ed07..ba9b4f6 100644
--- a/include/boost/mpl/lambda_fwd.hpp
+++ b/include/boost/mpl/lambda_fwd.hpp
@@ -18,6 +18,7 @@
 #define BOOST_MPL_LAMBDA_FWD_HPP_INCLUDED
 
 #include "boost/mpl/aux_/lambda_arity_param.hpp"
+#include "boost/mpl/aux_/config/lambda.hpp"
 
 namespace boost {
 namespace mpl {