diff --git a/include/xlnt/utils/utf8string.hpp b/include/xlnt/utils/utf8string.hpp
index e30dacd2..f4f8ee59 100644
--- a/include/xlnt/utils/utf8string.hpp
+++ b/include/xlnt/utils/utf8string.hpp
@@ -25,6 +25,7 @@
 #include <vector>
 
 #include <utf8.h>
+#include <xlnt/xlnt_config.hpp> // for XLNT_CLASS
 
 #include <xlnt/xlnt_config.hpp>