This study investigated prospective risk factors for increases in body dissatisfaction in adolescent girls and boys in the Eating Among Teens Project. At the time of first assessment (Time 1), participants were a cohort of early adolescent girls (N = 440) and boys (N = 366) and a cohort of middle adolescent girls (N = 946) and boys (N = 764). Participants were followed up 5 years later (Time 2). Potential prospective risk factors examined included body mass index, socioeconomic status, ethnicity, parent dieting environment, peer environment, and psychological factors. Predictors of Time 2 body dissatisfaction were Time 1 body dissatisfaction, body mass index, socioeconomic status, being African American, friend dieting and teasing, self-esteem, and depression. However, the profile of predictors differed across the samples.