diff --git a/src/bin/rmattr.cpp b/src/bin/rmattr.cpp
index 3053265a77..4603a16911 100644
--- a/src/bin/rmattr.cpp
+++ b/src/bin/rmattr.cpp
@@ -14,6 +14,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <fcntl.h>  // For O_WRONLY in BeOS R5 headers.
 #include <kernel/fs_attr.h>
 
 int main(int32 argc, const char **argv)