diff --git a/src/ZeekString.h b/src/ZeekString.h
index 7458a85427..8e769f4154 100644
--- a/src/ZeekString.h
+++ b/src/ZeekString.h
@@ -4,6 +4,7 @@
 
 #include <sys/types.h>
 #include <iosfwd>
+#include <string>
 #include <string_view>
 #include <vector>