This study tested potential mediators of a school-based skin cancer prevention intervention for middle school children (6th-8th grades; N = 1,788). Ten variables were tested on 4 criteria to establish mediation, including (a) intervention related to outcome, (b) intervention related to mediators, (c) mediators related to outcome, and (d) mediated effect statistically significant. Sun-safe behaviors (e.g., sunscreen use) and potential mediators were measured with a self-report questionnaire. All criteria were met for Barriers--Sunscreen, Perceived Self-Efficacy, and Knowledge when the mediators were tested separately. In multiple mediator analyses, barriers to sunscreen use and self-efficacy satisfied Criteria 1-3 but were not statistically significant (Criterion 4). Barriers to sunscreen use, perceived self-efficacy for sun-safe behavior, and knowledge may serve as mediators.