diff --git a/strings/base_types.h b/strings/base_types.h
index 12a9a600e..8bfc2f49c 100644
--- a/strings/base_types.h
+++ b/strings/base_types.h
@@ -79,13 +79,18 @@ WINRT_EXPORT namespace winrt
 
     inline bool operator==(guid const& left, guid const& right) noexcept
     {
-        return !memcmp(&left, &right, sizeof(guid));
+        return !memcmp(&left, &right, sizeof(left));
     }
 
     inline bool operator!=(guid const& left, guid const& right) noexcept
     {
         return !(left == right);
     }
+    
+    inline bool operator<(guid const& left, guid const& right) noexcept
+    {
+        return memcmp(&left, &right, sizeof(left)) < 0;
+    }
 }
 
 WINRT_EXPORT namespace winrt::Windows::Foundation