Although sports are popular activities for adolescents, the emphasis on winning at all costs, prevalent in adult competition models, might hinder moral development in youth. Therefore, this article reports the results of two studies investigating adolescent attitudes toward the acceptance of sports aggression from an integrated theoretical perspective. We developed a theoretical model using multiple variables indicating cohering and incohering performance dispositions. Moral engagement, positive affect, and less aggression characterized the cohering performance disposition. Moral disengagement, negative affect, and more aggression characterized the incohering performance disposition. The first study involved 332 Italian adolescents selected via convenience sampling. We used multiple-group structural equation modeling to test the model for differences between regions and gender among Italian adolescents. Findings indicated that the acceptance of sports aggression could be predicted by an integrated model based on performance dispositions. Further, adolescents who were already in a negative state and who characterized themselves as generally aggressive were more likely to accept sports aggression. Also, participating in sports was not a statistically significant predictor of sports aggression, and it was the adolescents in an incohering dispositional mode who were more accepting of aggressive tactics in sports. The second study tested a similar model for equivalency with 96 adolescents in the United States, identified through convenience sampling. With the U. S. sample, the model was adequately equivalent and accounted for 54% of variation in the acceptance of sports aggression. These studies contribute to the understanding of adolescents and their attitudes towards unethical sports behavior and moral decisions.