diff --git a/lib/std/c.zig b/lib/std/c.zig
index 57852d4830..de7e573378 100644
--- a/lib/std/c.zig
+++ b/lib/std/c.zig
@@ -1599,7 +1599,7 @@ pub const MADV = switch (native_os) {
         pub const SEQUENTIAL = 0x5;
         pub const RANDOM = 0x6;
     },
-    .netbsd => struct {
+    .netbsd, .openbsd => struct {
         pub const NORMAL = 0;
         pub const RANDOM = 1;
         pub const SEQUENTIAL = 2;