The purpose of this dissertation was to examine the relationships between moral judgments, affect, moral disengagement, general aggression, and the self-reported attitudes toward the acceptance of aggression in sports among Italian adolescents. Several research questions guided this investigation: 1) Can moral disengagement, maturation, affect, and sports experience predict the acceptance of aggression in sports? 2) Are there significant differences in a model of acceptance of aggression between male and female participants? 3) Are there significant differences in a model of acceptance of aggression between participants in Northern Italy and Southern Italy? Three hundred thirty-two adolescents from two high schools in northern and southern Italy participated in the study. They completed a demographic questionnaire about their age, gender, height, weight, main sport, years they have played their main sport, and the level of competition. They also completed five questionnaires on moral decision-making in sports, moral disengagement, a general aggression scale, a scale measuring positive and negative affect, and the Defining Issues Test-2. Data were analyzed using structural equation modeling to identify a model of adolescents who are more likely to approve of sports aggression. The results indicated that the acceptance of sports aggression could be predicted by an integrated model based on the biofunctional modes of constructive and unconstructive functioning. It was found that adolescents who were already in a negative state and who characterized themselves as generally aggressive were more likely to accept sports aggression. Those who participated in sports were more likely to have a positive disposition, which was not a significant factor in accepting sports aggression. The results indicated that participating in sports was not a significant predictor of sports aggression, and it was the adolescents in an unconstructive dispositional mode who were more accepting of aggressive tactics in sports. This dissertation contributes to our understanding of adolescents and their attitudes towards unethical sports behavior and moral decisions.