diff --git a/tests/zfs-tests/cmd/readmmap.c b/tests/zfs-tests/cmd/readmmap.c
index 704ffd55c8..a5c8079d0e 100644
--- a/tests/zfs-tests/cmd/readmmap.c
+++ b/tests/zfs-tests/cmd/readmmap.c
@@ -44,6 +44,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/mman.h>
+#include <sys/types.h>
 #include <time.h>
 
 int