Many Americans are familiar with the First Amendment, but its application to prayer and religious activities in public schools is often misunderstood. Religious beliefs are increasingly diverse in the United States. Therefore, it seems imperative that school personnel are aware of the law and sensitive to an array of religious practices. We conducted two studies that explored school personnel's (a) understanding of laws on religious expression in public schools; (b) attitudes toward religious expression in public schools; and (c) tolerance for different religions. Key Study 1 findings were that school personnel with more service years had less accurate knowledge of religious expression laws than school personnel with fewer service years, and more knowledge was related to increased sensitivity to religious practices in schools. Study 2 conceptually replicated these relations with a sample of pre-service teachers and found that Right-wing Authoritarianism mediated the relation between knowledge of the law and religious sensitivity, presenting an avenue for interventions to increase religious sensitivity.