Adolescence is a period of formative biological and social transition. Social cognitive processes involved in navigating an increasingly complex social world continue to develop throughout adolescence. Research in the past 15 years has demonstrated significant functional and structural changes in the brain during adolescence. Areas of the social brain undergo both structural changes and functional reorganization during the second decade of life, possibly reflecting a sensitive period for adapting to one's social environment. The changes in social environment that occur during adolescence might interact with increasing executive functions and heightened social sensitivity to influence a number of adolescent behaviours. I will discuss the importance of considering the social environment and social rewards in research on adolescent cognition and behaviour.