This paper aims to offer an alternative to the existing philosophical theories of self-deception. It describes and motivates a teleofunctional theory that models self-deception on the subintentional deceptions perpetrated by non-human organisms. Existing theories of self-deception generate paradoxes, are empirically implausible, or fail to account for the distinction between self-deception and other kinds of motivated irrationality. Deception is not a uniquely human phenomenon: biologists have found that many non-human organisms deceive and are deceived. A close analysis of the pollination strategy (...) of the mirror orchid (Ophrys speculum) provides the basis for an analysis of non-human deception as subintentionally purposive. This teleofunctional analysis is then used as the basis for a theory of self-deception that accounts for its normative and purposive features without defaulting to intentionalism. The teleofunctional theory accounts for distinction between self-deception and phenomena such as wishful thinking in an empirically plausible manner. Three objections to the theory are considered and rejected. (shrink)