This chapter examines the unique relationship between religion and public education in Japan, a country where no public school offers a formal course called “religion,” and where the boundaries between secular and religious education have been the subject of persistent controversy. Since 1945, debates have centered around whether public schools should promote the “education of religious sentiment,” reflecting broader ideological divisions between conservative and progressive forces. The chapter outlines the legal and historical frameworks shaping these debates, including key constitutional and legislative provisions that both guarantee religious freedom and prohibit confessional religious instruction in public education. Through an analysis of court cases such as the “Sunday Class Observation Case” and the “Kendo Refusal and Expulsion Case,” the chapter explores how conflicts between the religious rights of minorities and the principle of secularism are addressed in Japanese schools. The increasing cultural and religious pluralism since the 1990s, driven by immigration, has brought new challenges, particularly regarding the accommodation of religious minorities and the integration of non-Japanese children to Japanese school culture. However, the government has not established comprehensive guidelines for teaching about religion or for responding to the needs of students from different religious backgrounds. The chapter also discusses how the implicit norms and rituals of Japanese school culture—such as entrance and graduation ceremonies—can have quasi-religious or ritualistic dimensions, influencing how diversity and conformity are negotiated.