diff --git a/include/boost/mp11/algorithm.hpp b/include/boost/mp11/algorithm.hpp
index 126d359..e717368 100644
--- a/include/boost/mp11/algorithm.hpp
+++ b/include/boost/mp11/algorithm.hpp
@@ -48,8 +48,6 @@ namespace detail
 
 template<template<class...> class F, class... L> struct mp_transform_impl;
 
-template<template<class...> class F, class... L> using mp_transform = typename mp_transform_impl<F, L...>::type;
-
 template<template<class...> class F, template<class...> class L, class... T> struct mp_transform_impl<F, L<T...>>
 {
     using type = L<F<T>...>;
diff --git a/include/boost/mp11/map.hpp b/include/boost/mp11/map.hpp
index ffe3090..92c5164 100644
--- a/include/boost/mp11/map.hpp
+++ b/include/boost/mp11/map.hpp
@@ -12,6 +12,7 @@
 #include <boost/mp11/list.hpp>
 #include <boost/mp11/integral.hpp>
 #include <boost/mp11/utility.hpp>
+#include <boost/mp11/algorithm.hpp>
 #include <type_traits>
 
 namespace boost
@@ -24,6 +25,26 @@ template<class M, class K> using mp_map_contains = mp_not<std::is_same<mp_map_fi
 template<class M, class T> using mp_map_insert = mp_if< mp_map_contains<M, mp_first<T>>, M, mp_push_back<M, T> >;
 
 // mp_map_replace<M, T>
+namespace detail
+{
+
+template<class M, class T> struct mp_map_replace_impl;
+
+template<template<class...> class M, class... U, class T> struct mp_map_replace_impl<M<U...>, T>
+{
+    using K = mp_first<T>;
+
+    // mp_replace_if is inlined here using a struct _f because of msvc-14.0
+
+    template<class V> struct _f { using type = mp_if< std::is_same<mp_first<V>, K>, T, V >; };
+
+    using type = mp_if< mp_map_contains<M<U...>, K>, M<typename _f<U>::type...>, M<U..., T> >;
+};
+
+} // namespace detail
+
+template<class M, class T> using mp_map_replace = typename detail::mp_map_replace_impl<M, T>::type;
+
 // mp_map_update<M, T, F>
 // mp_map_erase<M, K>
 
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index c4e9919..6d2c767 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -93,3 +93,4 @@ run mp_or.cpp : : : $(REQ) ;
 run mp_map_find.cpp : : : $(REQ) ;
 run mp_map_contains.cpp : : : $(REQ) ;
 run mp_map_insert.cpp : : : $(REQ) ;
+run mp_map_replace.cpp : : : $(REQ) ;
diff --git a/test/mp_map_insert.cpp b/test/mp_map_insert.cpp
index 5137145..b334c9f 100644
--- a/test/mp_map_insert.cpp
+++ b/test/mp_map_insert.cpp
@@ -53,7 +53,7 @@ int main()
     }
 
     {
-        using M = mp_list<mp_list<int>, std::pair<long, long>, std::tuple<long long, long long, long long>>;
+        using M = std::tuple<mp_list<int>, std::pair<long, long>, std::tuple<long long, long long, long long>>;
 
         BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_insert<M, mp_list<char>>, mp_push_back<M, mp_list<char>>>));
         BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_insert<M, std::pair<char, char const>>, mp_push_back<M, std::pair<char, char const>>>));
diff --git a/test/mp_map_replace.cpp b/test/mp_map_replace.cpp
new file mode 100644
index 0000000..416a0fb
--- /dev/null
+++ b/test/mp_map_replace.cpp
@@ -0,0 +1,66 @@
+
+// Copyright 2016 Peter Dimov.
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+
+
+#include <boost/mp11/map.hpp>
+#include <boost/mp11/list.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+int main()
+{
+    using boost::mp_map_replace;
+    using boost::mp_list;
+    using boost::mp_push_back;
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<mp_list<>, mp_list<void>>, mp_list<mp_list<void>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<std::tuple<>, std::tuple<int>>, std::tuple<std::tuple<int>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<std::tuple<>, std::pair<int, float>>, std::tuple<std::pair<int, float>>>));
+
+    {
+        using M = mp_list<std::pair<int, int const>, std::pair<long, long const>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<char>>, mp_push_back<M, mp_list<char>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<char, char const>>, mp_push_back<M, std::pair<char, char const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<int>>, mp_list<mp_list<int>, std::pair<long, long const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<long, float>>, mp_list<std::pair<int, int const>, std::pair<long, float>>>));
+    }
+
+    {
+        using M = std::tuple<std::pair<int, int const>, std::pair<long, long const>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<char>>, mp_push_back<M, mp_list<char>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<char, char const>>, mp_push_back<M, std::pair<char, char const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<int>>, std::tuple<mp_list<int>, std::pair<long, long const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<long, float>>, std::tuple<std::pair<int, int const>, std::pair<long, float>>>));
+    }
+
+    {
+        using M = mp_list<mp_list<int>, mp_list<long, long>, mp_list<long long, long long, long long>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<char>>, mp_push_back<M, mp_list<char>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<char, char const>>, mp_push_back<M, std::pair<char, char const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::tuple<int>>, mp_list<std::tuple<int>, mp_list<long, long>, mp_list<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<long, float>>, mp_list<mp_list<int>, std::pair<long, float>, mp_list<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<long long, float, double>>, mp_list<mp_list<int>, mp_list<long, long>, mp_list<long long, float, double>>>));
+    }
+
+    {
+        using M = std::tuple<mp_list<int>, std::pair<long, long>, std::tuple<long long, long long, long long>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<char>>, mp_push_back<M, mp_list<char>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<char, char const>>, mp_push_back<M, std::pair<char, char const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::tuple<int>>, std::tuple<std::tuple<int>, std::pair<long, long>, std::tuple<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, std::pair<long, float>>, std::tuple<mp_list<int>, std::pair<long, float>, std::tuple<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_replace<M, mp_list<long long, float, double>>, std::tuple<mp_list<int>, std::pair<long, long>, mp_list<long long, float, double>>>));
+    }
+
+    return boost::report_errors();
+}