Prayer constituted a core element of character and patriotic formation at the outset of the American public education system in the colonial period. Over the years, however, the status of this religious practice has undergone a significant transformation, including a complete ban on school prayer. The article discusses the factors that have had a decisive impact on the status of school prayer, including increasing religious diversity of the American population as well as tensions between dominant and minority religions and non-religion. Both old controversies over state-sponsored and school-run prayer as well as more recent ones surrounding graduation prayer and prayer before sports games will be discussed in more detail on the basis of landmark Supreme Court and lower court cases as well as government regulations, including presidential guidelines and other administrative documents.