This article reports on the formation of pre-service teachers for religious education through an experiential learning program called the Retreat Leaders Training Program (RLTP). First, the article examines the need for formation for pre-service RE teachers, especially as the formation relates to the development of three forms of teacher knowledge: content knowledge, pedagogical content knowledge and experiential content knowledge. Second, the article reviews the literature on the role of experiential learning in professional formation and the contribution live-in retreats may make in this formation. Third, the article presents the Retreat Leaders Training Program as an example of the formative influence of a retreat based on experiential learning. Fourth, feedback from pre-service teachers undertaking the 2011 program is reported. Lastly, the article discusses the outcomes of the RLTP and the significance of the program as a key ingredient in the formation of teacher knowledge for religious education.