Issues of spirituality and thriving are pertinent to the period of adolescence given the marked changes in body, mind, and relationships. In order to provide an overview of the relationship between religion, spirituality, and positive youth development, this chapter offers a developmental systems perspective and proposes a relational spirituality as a framework for understanding adolescent religious and spiritual development. In addition, the chapter examines various psychological mechanisms through which religion and spirituality may promote positive youth development. Existing empirical research on the relationships between adolescent religion, spirituality, thriving, and specific indicators of positive youth development is reviewed. Finally, future directions for continuing to build the field of study are discussed.