diff --git a/tdutils/td/utils/OptionsParser.h b/tdutils/td/utils/OptionsParser.h
index e02f82d68..3fd76859f 100644
--- a/tdutils/td/utils/OptionsParser.h
+++ b/tdutils/td/utils/OptionsParser.h
@@ -16,6 +16,7 @@
 
 #if !TD_WINDOWS
 #include <getopt.h>
+#include <unistd.h>
 #endif
 
 namespace td {