diff --git a/include/llvm/ADT/Triple.h b/include/llvm/ADT/Triple.h
index 3fccf41841d..84e0b29d1fe 100644
--- a/include/llvm/ADT/Triple.h
+++ b/include/llvm/ADT/Triple.h
@@ -14,6 +14,7 @@
 
 // Some system headers or GCC predefined macros conflict with identifiers in
 // this file.  Undefine them here.
+#undef NetBSD
 #undef mips
 #undef sparc