diff --git a/include/boost/mp11/set.hpp b/include/boost/mp11/set.hpp
index b3917db..54f5f42 100644
--- a/include/boost/mp11/set.hpp
+++ b/include/boost/mp11/set.hpp
@@ -13,6 +13,7 @@
 #include <boost/mp11/detail/mp_list.hpp>
 #include <boost/mp11/detail/mp_append.hpp>
 #include <boost/mp11/detail/mp_remove_if.hpp>
+#include <boost/mp11/detail/mp_is_list.hpp>
 #include <type_traits>
 
 namespace boost
@@ -144,7 +145,7 @@ template<class... S> struct in_any_set
 
 } // namespace detail
 
-template<class L, class... S> using mp_set_difference = mp_remove_if_q<L, detail::in_any_set<S...>>;
+template<class L, class... S> using mp_set_difference = mp_if< mp_all<mp_is_list<S>...>, mp_remove_if_q<L, detail::in_any_set<S...>> >;
 
 } // namespace mp11
 } // namespace boost
diff --git a/test/Jamfile b/test/Jamfile
index ba34e7a..ba715e3 100644
--- a/test/Jamfile
+++ b/test/Jamfile
@@ -136,6 +136,7 @@ run mp_is_set.cpp ;
 run mp_set_union.cpp ;
 run mp_set_union_sf.cpp ;
 run mp_set_difference.cpp ;
+run mp_set_difference_sf.cpp ;
 
 # function
 run mp_all.cpp ;
diff --git a/test/mp_set_difference_sf.cpp b/test/mp_set_difference_sf.cpp
new file mode 100644
index 0000000..ddcb63d
--- /dev/null
+++ b/test/mp_set_difference_sf.cpp
@@ -0,0 +1,33 @@
+
+// Copyright 2019 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/set.hpp>
+#include <boost/mp11/utility.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+int main()
+{
+    using boost::mp11::mp_set_difference;
+    using boost::mp11::mp_valid;
+    using boost::mp11::mp_list;
+
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, void, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, void, void, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, void, void, void, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, void, void, void, void, void>));
+
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, mp_list<>, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, mp_list<>, mp_list<>, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, mp_list<>, mp_list<>, mp_list<>, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_difference, mp_list<>, mp_list<>, mp_list<>, mp_list<>, void>));
+
+    return boost::report_errors();
+}