Abstract Purpose To evaluate the effectiveness of Student Bodies, an Internet-delivered eating disorder prevention program for adolescents, and a supplemental program for their parents. Methods One hundred fifty-two 10th grade females completing a health course at a private sectarian school, and 69 of their parents were assigned to either the Internet-delivered intervention group or to a comparison group (students) or wait-list control group (parents). Student participants completed subscales of the Eating Disorder Inventory, Eating Disorder Examination-Questionnaire, and a content knowledge test. Parents completed the Parental Attitudes and Criticism Scale. Results The main effects of the intervention were assessed pre- to post- and post- to follow-up using ANCOVA, with the baseline assessment of the independent variable as the covariate. Students using the program reported significantly reduced eating restraint and had significantly greater increases in knowledge than did students in the comparison group. However, there were no significant differences at follow-up. Parents significantly decreased their overall critical attitudes toward weight and shape. Conclusion The program demonstrates the feasibility of providing an integrated program for students and their parents with short-term positive changes in parental attitudes toward weight and shape.