Although psychologists have long recognized the havoc that a discovered lie can wreak on a relationship, this study indicates that even an undiscovered deception can bring about negative consequences. An experiment explored one such consequence by examining the hypothesis that in a dyadic relationship, if one partner lies to the other, the liar will begin to perceive the recipient as less honest. Participants who were induced to lie to a partner in a believable and, in some conditions, damaging manner then rated the partner on a variety of traits, including honesty. The results indicated a significant reduction in perceived honesty of the recipient of the lie, particularly by participants who told damaging lies. An exploration into the underlying mechanisms of the effect suggested that deceiver's distrust operates through affective means, with the liars justifying their actions in a self-protection motivated version of the false consensus effect.