diff --git a/include/cxxopts.hpp b/include/cxxopts.hpp
index 870755a2..12456a70 100644
--- a/include/cxxopts.hpp
+++ b/include/cxxopts.hpp
@@ -2243,6 +2243,7 @@ OptionParser::parse(int argc, const char* const* argv)
           {
             if (m_allow_unrecognised)
             {
+              unmatched.push_back(std::string("-") + s[i]);
               continue;
             }
             //error
diff --git a/test/options.cpp b/test/options.cpp
index 0e861779..610a6bc9 100644
--- a/test/options.cpp
+++ b/test/options.cpp
@@ -656,6 +656,7 @@ TEST_CASE("Unrecognised options", "[options]") {
     "--long",
     "-su",
     "--another_unknown",
+    "-a",
   });
 
   auto** argv = av.argv();
@@ -669,7 +670,7 @@ TEST_CASE("Unrecognised options", "[options]") {
     options.allow_unrecognised_options();
     auto result = options.parse(argc, argv);
     auto& unmatched = result.unmatched();
-    CHECK((unmatched == std::vector<std::string>{"--unknown", "--another_unknown"}));
+    CHECK((unmatched == std::vector<std::string>{"--unknown", "-u", "--another_unknown", "-a"}));
   }
 }