Nicholls's theory of achievement motivation (1989) assumes one's goal orientation in an achievement activity is consistent with one's views concerning what is acceptable behavior in that setting. The purpose of this study was to determine the relationship of a task and ego goal orientation (i.e., the tendency to focus on personal mastery or beating others, respectively) to sportsmanship attitudes and perceptions of the legitimacy of aggressive acts by testing this assumption in the context of interscholastic sport. Fifty-six male and 67 female high school basketball players completed a three-part questionnaire assessing (a) individual differences in goal orientation, (b) approval of "unsportsmanlike play/cheating," "strategic play," and "sportsmanship behaviors," and (c) subjective ratings of the legitimacy of intentionally injurious behaviors. All measures were basketball-specific. Results indicated a low task orientation and high ego orientation corresponded to an endorsement of unsportsmanlike play/cheating. Ego orientation positively related to the rating of aggressive acts as more legitimate. Gender differences in goal orientation, sportsmanship attitudes, and legitimacy ratings were observed.