Atheists have long been distrusted, in part because they do not believe that a watchful, judging god monitors their behavior. However, in many parts of the world, secular institutions such as police, judges, and courts are also potent sources of social monitoring that encourage prosocial behavior. Reminders of such secular authority could therefore reduce believers’ distrust of atheists. In our experiments, participants who watched a video about police effectiveness (Experiment 1) or were subtly primed with secular-authority concepts (Experiments 2–3) expressed less distrust of atheists than did participants who watched a control video or were not primed, respectively. We tested three distinct alternative explanations for these findings. Compared with control participants, participants primed with secular-authority concepts did not exhibit reduced general prejudice against out-groups (Experiment 1), prejudice reactions associated with functional threats that particular out-groups are perceived to pose (specifically, viewing gays with disgust; Experiment 2), or general distrust of out-groups (Experiment 3). These findings contribute to theory regarding both the psychological bases of prejudices and the psychological functions served by gods and governments.