The current study examined longitudinal cross-lagged associations between prosocial TV (content and time) and prosocial and aggressive behavior during adolescence, and explored the mediating role of empathic concern and self-regulation. Participants were 441 adolescents who reported on their 3 favorite TV shows at 2 time points, approximately 2 years apart (M age of child at Time 3 = 13.31, SD = 1.06; 52% female; M age of child at Time 5 = 15.27, SD = 1.06). Results suggested that prosocial content at Time 3 was negatively associated with aggressive behavior 2 years later, and aggressive behavior at Time 3 was positively associated with aggressive content 2 years later. Results also suggested that prosocial behavior toward strangers at Time 3 was associated with both empathic concern and self-regulation at Time 4, which were in turn associated with prosocial and aggressive content at Time 5. Discussion focuses on the important role of behavior and prosocial personality on media selection during adolescence and the relevance of the target of prosocial behavior.