Authorities frequently justify their sanctions as attempts to deter people from rule breaking. Although providing a sanction justification seems appealing and harmless, we propose that a deterrence justification decreases the extent to which sanctions are effective in promoting rule compliance. We develop a theoretical model that specifies how and why this occurs. Consistent with our model, 5 experiments demonstrated that—compared with sanctions provided without a justification or sanctions provided with a just-deserts justification—sanction effectiveness decreased when sanctions were justified as attempts to deter people from rule breaking. This effect was mediated by people feeling distrusted by the authority. We further demonstrated that (a) the degree to which deterrence fostered distrust was attenuated when the sanction was targeted at others (instead of the participant) and (b) the degree to which distrust undermined rule compliance was attenuated when the authority was perceived as legitimate. We discuss the practical implications for authorities tasked with promoting rule compliance, and the theoretical implications for the literature on sanctions, distrust, and rule compliance.