diff --git a/help.c b/help.c
index 5483ea8fd2..d3d3adcc5c 100644
--- a/help.c
+++ b/help.c
@@ -2,6 +2,7 @@
 #define DISABLE_SIGN_COMPARE_WARNINGS
 
 #include "git-compat-util.h"
+#include "git-zlib.h"
 #include "config.h"
 #include "builtin.h"
 #include "exec-cmd.h"