In many Western countries, more and more people are living longer. As part of this demographic shift, increasing numbers are participating in Masters sport. In the past, sport was considered important for the development of young people;however, the potential for sport participation to affect positive development across the lifespan is now recognized. The purpose of this paper is to introduce conceptual frameworks from developmental psychology that are being used to understand youths' positive development through sport, and to explore these frameworks in the context of sport as an avenue for positive development in older persons. To achieve this aim, we outline research on sport participation as it applies to youth development and consider relevant aspects as they broadly apply to development later in life. This discussion highlights the inherent paradox of sport participation'that it has the potential to provide considerable positive growth but also the potential for significant negative consequences. Finally, we explore areas of future research related to positive development in older persons through sport.