diff --git a/fuzz/input-fuzzer.c b/fuzz/input-fuzzer.c
index 0d80690b..049762b8 100644
--- a/fuzz/input-fuzzer.c
+++ b/fuzz/input-fuzzer.c
@@ -16,6 +16,7 @@
 
 #include <stddef.h>
 #include <assert.h>
+#include <fcntl.h>
 
 #include "tmux.h"