diff --git a/lib/std/os.zig b/lib/std/os.zig
index 5923f90a63c094a46318b5972d84e1c3ceca9acf..b3c82311238830db7559ea5ab90e0b990c9128e5 100644
--- a/lib/std/os.zig
+++ b/lib/std/os.zig
@@ -2538,7 +2538,7 @@ pub fn rmdirZ(dir_path: [*:0]const u8) DeleteDirError!void {
         .PERM => return error.AccessDenied,
         .BUSY => return error.FileBusy,
         .FAULT => unreachable,
-        .INVAL => unreachable,
+        .INVAL => return error.BadPathName,
         .LOOP => return error.SymLinkLoop,
         .NAMETOOLONG => return error.NameTooLong,
         .NOENT => return error.FileNotFound,