Objective: In this study, we explored the characteristics of moral disengagement in sport and its mediating role in athletes' goal orientations and their attitudes towards doping We enrolled 203 athletes in the study. Methods: The Task and Ego Orientation in Sports Questionnaire, Moral Disengagement in Sport Scale and Performance Enhancement Attitude Scale were used to assess athletes' goal orientations and attitudes toward doping. Results: Our findings revealed that: (1) male athletes' scores for moral disengagement were significantly higher than those of female athletes; and (2) moral disengagement completely mediated the relationship between ego orientation and attitude towards doping, and partially mediated the association between task orientation and attitude towards doping. Conclusions: Changing the moral cognition and lowering the level of moral disengagement in athletes may be important issues to include in anti-doping education.