diff --git a/drivers/unix/sub_process_unix.cpp b/drivers/unix/sub_process_unix.cpp
index bb2480dfa..2bf0985d8 100644
--- a/drivers/unix/sub_process_unix.cpp
+++ b/drivers/unix/sub_process_unix.cpp
@@ -38,6 +38,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/wait.h>
+#include <unistd.h>
 
 Error SubProcessUnix::start() {
 #ifdef __EMSCRIPTEN__