diff --git a/mrbgems/mruby-io/src/io.c b/mrbgems/mruby-io/src/io.c
index a5fe22e46..41cd581aa 100644
--- a/mrbgems/mruby-io/src/io.c
+++ b/mrbgems/mruby-io/src/io.c
@@ -34,6 +34,7 @@
 
 #else
   #include <sys/wait.h>
+  #include <sys/time.h>
   #include <unistd.h>
   typedef size_t fsize_t;
   typedef time_t ftime_t;