diff --git a/include/cantera/kinetics/ReactionData.h b/include/cantera/kinetics/ReactionData.h
index 89da9c51e3..f5ae68317f 100644
--- a/include/cantera/kinetics/ReactionData.h
+++ b/include/cantera/kinetics/ReactionData.h
@@ -11,6 +11,8 @@
 #ifndef CT_REACTIONDATA_H
 #define CT_REACTIONDATA_H
 
+#include "cantera/base/ct_defs.h"
+
 namespace Cantera
 {