Effects of a single session masturbation seminar en high school males' beliefs, guilt, and behavior regarding masturbation were examined. It was predicted that the treatment group would, as compared to a control group, (a) be more positive in their attitudes toward masturbation in general, (b) have fewer false beliefs about the harmful nature of masturbation (sex myths), (c) have less sex guilt associated with masturbating, and (d) report a greater frequency of masturbation. Results indicated that for the treatment group, attitudes were more positive toward masturbation in general, and there were fewer false beliefs. Negative feelings (e.g., guilt) were not influenced following instruction, nor was masturbatory behavior. These findings provide support for a multivariate construct approach to studying masturbation attitudes and behavior. The present study also offers some support for the inclusion of seminars about adolescent masturbation in similar sex education programs