Abstract Background School-based comprehensive sexual health education can improve adolescent health outcomes, and web-based programs are a promising approach to overcoming challenges associated with teacher-led formats by ensuring that students receive content that is consistent, unbiased, and medically accurate. However, many adolescents do not receive high-quality sexual health education and turn to the media for information about sex and relationships. Consumption of sexual media messages is related to early and risky sexual behaviors. Media literacy education (MLE) is a proven approach to adolescent sexual health promotion, yet there are no rigorously evaluated web-based MLE programs to promote sexual and relationship health among high school students. Methods This study will test the efficacy, in a randomized controlled trial, of Media Aware, a web-based comprehensive sexual health promotion program for high school students that uses an MLE approach. Participants will be students in 9th and 10th grade h...