diff --git a/orm_lib/src/sqlite3_impl/Sqlite3Connection.cc b/orm_lib/src/sqlite3_impl/Sqlite3Connection.cc
index 15af657611..762b96beb6 100644
--- a/orm_lib/src/sqlite3_impl/Sqlite3Connection.cc
+++ b/orm_lib/src/sqlite3_impl/Sqlite3Connection.cc
@@ -17,6 +17,7 @@
 #include <drogon/utils/Utilities.h>
 #include <drogon/utils/string_view.h>
 #include <regex>
+#include <cctype>
 
 using namespace drogon;
 using namespace drogon::orm;