diff --git a/src/cxxopts.hpp b/src/cxxopts.hpp
index 4d1913d..4a00b4f 100644
--- a/src/cxxopts.hpp
+++ b/src/cxxopts.hpp
@@ -30,6 +30,7 @@ THE SOFTWARE.
 #pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
 #endif
 
+#include <cstring>
 #include <exception>
 #include <iostream>
 #include <map>