diff --git a/src/group.h b/src/group.h
index 9f44850d79..4c7dca0835 100644
--- a/src/group.h
+++ b/src/group.h
@@ -16,6 +16,7 @@
 
 #include "pointers.h"
 #include <map>
+#include <string>
 
 namespace LAMMPS_NS {