Objectives. We evaluated the effectiveness of an intervention designed to increase preventive health care seeking among adolescents. Methods. Adolescents and young adults aged 12 to 21 years, recruited from community-based organizations in 2 different communities, were randomized into either a 3-session intervention or a control condition. We estimated outcomes from 3-month follow-up data using logistic and ordinary least squares regression. Results. Female intervention participants were significantly more likely than female control participants to have scheduled a health care appointment (odds ratio [OR]=3.04), undergone a checkup (OR=2.87), and discussed with friends or family members the importance of undergoing a checkup (OR=4.5). There were no differences between male intervention and male control participants in terms of outcomes. Conclusions. This theory-driven, community-based group intervention significantly increased preventive health care seeking among female adolescents. Further research is needed, however, to identify interventions that will produce successful outcomes among male adolescents.