diff --git a/fish_tests.cpp b/fish_tests.cpp
index 317619245..c661474ff 100644
--- a/fish_tests.cpp
+++ b/fish_tests.cpp
@@ -15,6 +15,7 @@
 #include <termios.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
 #include <fcntl.h>
 #include <stdarg.h>
 #include <assert.h>