A great deal of work argues that people demand impartial, evidence-based reasoning from others. However, recent findings show that moral values occupy a cardinal position in people’s evaluation of others, raising the possibility that people sometimes prescribe morally-good but evidentially-poor beliefs. We report two studies investigating how people evaluate beliefs when these two ideals conflict and find that people regularly endorse motivated reasoning when it can be morally justified. Furthermore, we document two ways that moral considerations result in prescribed motivated reasoning. First, morality can provide an alternative justification for belief, leading people to prescribe evidentially unsupported beliefs to others. And, second, morality can affect how people evaluate the way evidence is weighed by lowering or raising the threshold of required evidence for morally good and bad beliefs, respectively. These results illuminate longstanding questions about the nature of motivated reasoning and the social regulation of belief.