The past decade's research on the use and effects of older (television, music, movies, magazines) and newer media (the Internet, cell phones, social networking) on adolescents' health and well-being is reviewed. A portrait of patterns of use of the media is provided and then the predictors and effects of those patterns on adolescents' mental health is discussed. Research on the effects of exposure to specific kinds of content on adolescents' aggressive behavior, gender roles, sexual relationships, body image disturbances, obesity, and substance use also are reviewed. Finally, media literacy as a promising strategy for enhancing adolescents' use of the media in the future is considered.