Most people believe in a god of some sort. Nonetheless, there are hundreds of millions of atheists in the world, and they face considerable discrimination and prejudice. This is a puzzling form of prejudice: Atheists do not form a coherent group, they are individually inconspicuous, and they are not, in general, oppositional or threatening. Recent research in social, evolutionary, and cultural psychology, however, offers suggestions for solving the puzzle of anti-atheist prejudice, in terms of both uncovering its psychological causes and also suggesting interventions for reducing it. Antipathy towards atheists derives specifically from moral distrust – to many people, belief in a watchful, moralizing god is seen as a uniquely powerful and perhaps necessary component of morality. Without religious belief, atheists are viewed as moral wildcards who cannot be trusted. This unique basis in turn implies specific ways in which distrust of atheists might be ameliorated.