diff --git a/include/boost/core/string_view.hpp b/include/boost/core/string_view.hpp
index 941891a..4cb120c 100644
--- a/include/boost/core/string_view.hpp
+++ b/include/boost/core/string_view.hpp
@@ -381,6 +381,35 @@ public:
 
     // BOOST_CONSTEXPR basic_string_view& operator=( basic_string_view const& ) BOOST_NOEXCEPT & = default;
 
+    // conversions
+
+#if !defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS)
+
+    template<class Ch2, class En = typename boost::enable_if<is_same<Ch2, Ch> >::type>
+    operator std::basic_string<Ch2>() const
+    {
+        return std::basic_string<Ch>( data(), size() );
+    }
+
+#else
+
+    operator std::basic_string<Ch>() const
+    {
+        return std::basic_string<Ch>( data(), size() );
+    }
+
+#endif
+
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
+
+    template<class Ch2, class En = typename boost::enable_if<is_same<Ch2, Ch> >::type>
+    operator std::basic_string_view<Ch2>() const BOOST_NOEXCEPT
+    {
+        return std::basic_string_view<Ch>( data(), size() );
+    }
+
+#endif
+
     // iterator support
 
     BOOST_CONSTEXPR const_iterator begin() const BOOST_NOEXCEPT
@@ -925,6 +954,198 @@ public:
     {
         return sv1.compare( sv2 ) >= 0;
     }
+
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
+
+    // "sufficient number of additional overloads"
+
+    // against std::string_view
+
+    BOOST_CXX14_CONSTEXPR friend bool operator==( basic_string_view sv1, std::basic_string_view<Ch> sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) == 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator==( std::basic_string_view<Ch> sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) == 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator!=( basic_string_view sv1, std::basic_string_view<Ch> sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) != 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator!=( std::basic_string_view<Ch> sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) != 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<( basic_string_view sv1, std::basic_string_view<Ch> sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) < 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<( std::basic_string_view<Ch> sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) < 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<=( basic_string_view sv1, std::basic_string_view<Ch> sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) <= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<=( std::basic_string_view<Ch> sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) <= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>( basic_string_view sv1, std::basic_string_view<Ch> sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) > 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>( std::basic_string_view<Ch> sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) > 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>=( basic_string_view sv1, std::basic_string_view<Ch> sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) >= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>=( std::basic_string_view<Ch> sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) >= 0;
+    }
+
+    // against Ch const*
+
+    BOOST_CXX14_CONSTEXPR friend bool operator==( basic_string_view sv1, Ch const* sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) == 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator==( Ch const* sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) == 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator!=( basic_string_view sv1, Ch const* sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) != 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator!=( Ch const* sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) != 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<( basic_string_view sv1, Ch const* sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) < 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<( Ch const* sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) > 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<=( basic_string_view sv1, Ch const* sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) <= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<=( Ch const* sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) >= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>( basic_string_view sv1, Ch const* sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) > 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>( Ch const* sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) < 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>=( basic_string_view sv1, Ch const* sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) >= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>=( Ch const* sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) <= 0;
+    }
+
+    // against std::string
+
+    BOOST_CXX14_CONSTEXPR friend bool operator==( basic_string_view sv1, std::basic_string<Ch> const& sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) == 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator==( std::basic_string<Ch> const& sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) == 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator!=( basic_string_view sv1, std::basic_string<Ch> const& sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) != 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator!=( std::basic_string<Ch> const& sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) != 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<( basic_string_view sv1, std::basic_string<Ch> const& sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) < 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<( std::basic_string<Ch> const& sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) > 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<=( basic_string_view sv1, std::basic_string<Ch> const& sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) <= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator<=( std::basic_string<Ch> const& sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) >= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>( basic_string_view sv1, std::basic_string<Ch> const& sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) > 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>( std::basic_string<Ch> const& sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) < 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>=( basic_string_view sv1, std::basic_string<Ch> const& sv2 ) BOOST_NOEXCEPT
+    {
+        return sv1.compare( sv2 ) >= 0;
+    }
+
+    BOOST_CXX14_CONSTEXPR friend bool operator>=( std::basic_string<Ch> const& sv1, basic_string_view sv2 ) BOOST_NOEXCEPT
+    {
+        return sv2.compare( sv1 ) <= 0;
+    }
+
+#endif
 };
 
 template<class Ch> std::basic_ostream<Ch>& operator<<( std::basic_ostream<Ch>& os, basic_string_view<Ch> str )
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index b6c89b5..7a1912c 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -267,6 +267,7 @@ run sv_contains_test.cpp ;
 run sv_eq_test.cpp ;
 run sv_lt_test.cpp ;
 run sv_stream_insert_test.cpp ;
+run sv_conversion_test.cpp ;
 
 use-project /boost/core/swap : ./swap ;
 build-project ./swap ;
diff --git a/test/sv_conversion_test.cpp b/test/sv_conversion_test.cpp
new file mode 100644
index 0000000..fb77e8d
--- /dev/null
+++ b/test/sv_conversion_test.cpp
@@ -0,0 +1,38 @@
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/core/string_view.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <string>
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
+# include <string_view>
+#endif
+
+boost::core::string_view f( boost::core::string_view const& str )
+{
+    return str;
+}
+
+int main()
+{
+    {
+        std::string s1( "123" );
+        std::string s2 = f( s1 );
+
+        BOOST_TEST_EQ( s1, s2 );
+    }
+
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
+
+    {
+        std::string_view s1( "123" );
+        std::string_view s2 = f( s1 );
+
+        BOOST_TEST_EQ( s1, s2 );
+    }
+
+#endif
+
+    return boost::report_errors();
+}