diff --git a/src/libutil/types.hh b/src/libutil/types.hh
index 3af485fa0..2170e4c93 100644
--- a/src/libutil/types.hh
+++ b/src/libutil/types.hh
@@ -4,6 +4,7 @@
 
 #include <list>
 #include <set>
+#include <string>
 #include <map>
 #include <vector>