Abstract. Across three studies, we assessed the impact of perceived social norms on attitudes and positive behavioral intentions towards atheists and religious believers. Reported attitudes, reported acceptability of expressing positive and negative attitudes, and reported positive behavioral intentions disproportionately favored religious believers over atheists. However, participants reported a higher likelihood of engaging in positive behaviors towards atheists when the threat of public scrutiny was limited, indicating that the social norm in the US may be suppressing privately held, positive behavioral intentions that would otherwise support atheists, creating a state of pluralistic ignorance. Individuals also reported having more positive attitudes and a higher level of positive behavioral intentions towards religious believers relative to others. Finally, estimates of the prevalence of religious believers in the population also tied directly to one’s perception of the acceptability of expressing positive and negative attitudes towards these groups.