A satisfactory analysis of human deception must rule out cases where it is a mistake or an accident that person B was misled by person A's behavior. Therefore, most scholars think that deceivers must intend to deceive. This article argues that there is a better solution: rather than appealing to the deceiver's intentions, we should appeal to the function of their behavior. After all, animals and plants engage in deception, and most of them are not capable of forming intentions. Accordingly, (...) certain human behavior is deceptive if and only if its function is to mislead. This solves our problem because if the function of A's behavior was to mislead, B's ending up misled was not an accident or a mere mistake even if A did not intend to deceive B. (shrink)