In this article I argue that it is possible to find, in the Groundwork, a perfect ethical duty to others not to lie to any other person, ever. This duty is not in the Doctrine of Virtue, or the Right to Lie essay. It is an exceptionless, negative duty. The argument given for this negative duty from the Universal Law formula of the Categorical Imperative is that the liar necessarily applies a double standard: do not lie (everyone else), and lie (...) (the liar). The basis for this double standard is a presumption of inequality: the liar treats others as less than her. However, this argument fails to exclude lies told to liars, since the liar applies a single standard in this case: (secretly) lie to those whom you believe are lying to you. The argument given for this negative duty from the Humanity formula of the Categorical Imperative is that the liar necessarily behaves in way towards the other person in a way to which she "cannot possibly" consent. However, this argument fails to exclude lies told to those who have consented to be lied to, without knowing which lies they are to be told. Kant's arguments, therefore, fail to generate a perfect exceptionalness negative duty not to lie to any person, ever. (shrink)