diff --git a/include/boost/variant2/variant.hpp b/include/boost/variant2/variant.hpp
index 9f1f517..0f14659 100644
--- a/include/boost/variant2/variant.hpp
+++ b/include/boost/variant2/variant.hpp
@@ -2263,6 +2263,13 @@ template<class Os, class T> struct is_output_streamable<Os, T, decltype( std::de
 
 } // namespace detail
 
+template<class Ch, class Tr>
+std::basic_ostream<Ch, Tr>& operator<<( std::basic_ostream<Ch, Tr>& os, monostate const& )
+{
+    os << "monostate";
+    return os;
+}
+
 template<class Ch, class Tr, class T1, class... T,
     class E = typename std::enable_if< mp11::mp_all< detail::is_output_streamable<std::basic_ostream<Ch, Tr>, T>... >::value >::type >
 std::basic_ostream<Ch, Tr>& operator<<( std::basic_ostream<Ch, Tr>& os, variant<T1, T...> const& v )
diff --git a/test/is_output_streamable.cpp b/test/is_output_streamable.cpp
index 6d0f0a2..1b0f2fe 100644
--- a/test/is_output_streamable.cpp
+++ b/test/is_output_streamable.cpp
@@ -30,9 +30,12 @@ int main()
     BOOST_TEST_TRAIT_FALSE((boost::variant2::detail::is_output_streamable<std::ostream, X>));
     BOOST_TEST_TRAIT_TRUE((boost::variant2::detail::is_output_streamable<std::ostream, Y>));
 
+    BOOST_TEST_TRAIT_TRUE((boost::variant2::detail::is_output_streamable<std::ostream, boost::variant2::monostate>));
+
     BOOST_TEST_TRAIT_TRUE((boost::variant2::detail::is_output_streamable<std::ostream, boost::variant2::variant<int, float, std::string>>));
     BOOST_TEST_TRAIT_FALSE((boost::variant2::detail::is_output_streamable<std::ostream, boost::variant2::variant<int, float, X>>));
     BOOST_TEST_TRAIT_TRUE((boost::variant2::detail::is_output_streamable<std::ostream, boost::variant2::variant<int, float, Y>>));
+    BOOST_TEST_TRAIT_TRUE((boost::variant2::detail::is_output_streamable<std::ostream, boost::variant2::variant<boost::variant2::monostate, int, float>>));
 
     return boost::report_errors();
 }
diff --git a/test/variant_ostream_insert.cpp b/test/variant_ostream_insert.cpp
index 34fda07..fca7fe6 100644
--- a/test/variant_ostream_insert.cpp
+++ b/test/variant_ostream_insert.cpp
@@ -20,17 +20,24 @@ template<class T> std::string to_string( T const& t )
 
 int main()
 {
-    variant<int, float, std::string> v( 1 );
+    {
+        BOOST_TEST_EQ( to_string( monostate() ), "monostate" );
+    }
 
-    BOOST_TEST_EQ( to_string( v ), to_string( 1 ) );
+    {
+        variant<monostate, int, float, std::string> v;
 
-    v = 3.14f;
+        BOOST_TEST_EQ( to_string( v ), to_string( monostate() ) );
 
-    BOOST_TEST_EQ( to_string( v ), to_string( 3.14f ) );
+        v = 1;
+        BOOST_TEST_EQ( to_string( v ), to_string( 1 ) );
 
-    v = "test";
+        v = 3.14f;
+        BOOST_TEST_EQ( to_string( v ), to_string( 3.14f ) );
 
-    BOOST_TEST_EQ( to_string( v ), to_string( "test" ) );
+        v = "test";
+        BOOST_TEST_EQ( to_string( v ), to_string( "test" ) );
+    }
 
     return boost::report_errors();
 }