Peer Health Exchange (PHE) trains college students to teach health education in under-resourced high schools across the country. Volunteers teach a full-year curriculum in which students develop skills in decision-making (e.g., how to identify consequences), communications and advocacy (e.g., consent and refusal skills), and accessing resources (e.g., how to identify valid information on the internet). PHE has a statistically-significant positive effect on sexual and mental knowledge, skills, and help-seeking behavior. PHE volunteers reach more than 15,000 high school students annually.