diff --git a/include/cxxopts.hpp b/include/cxxopts.hpp
index 6677002..04c58c3 100644
--- a/include/cxxopts.hpp
+++ b/include/cxxopts.hpp
@@ -1281,7 +1281,7 @@ namespace cxxopts
     }
 
     std::string
-    help(const std::vector<std::string>& groups = {""}) const;
+    help(const std::vector<std::string>& groups = {}) const;
 
     const std::vector<std::string>
     groups() const;