The efficacy of a school-based intervention was evaluated using a randomized controlled trial in Australia. In consecutive grades (8, 9, and 10), students in the intervention group received components of a program that addressed issues related to the need to protect yourself from the sun, behavioral strategies related to using sun-protective measures, personal and social images of having a tan, the use of sun-safe clothing, and how to change their schools through forms of structural change. Pre- and postintervention measures among junior high school students showed greatest improvement in the intervention group's knowledge scores and minimal changes in sun protection behavior from Grade 8 to Grade 9, which were not maintained through Grade 10. Results of the study highlight some limitations of school-based interventions for changing sun protection behaviors.