What role does reasoning about moral principles play in people’s judgments about what is right or wrong? According to one view, reasoning usually plays little role. People tend to do what suits their self-interests and concoct moral reasons afterward to justify their own behavior. Thus, in this view, people are far more forgiving of their own violations than of others’ violations. According to a contrasting view, principled reasoning generally guides judgments and decisions about our own and others’ actions. This view predicts that people usually can, and do, articulate the principles that guide their moral judgments and decisions. The present research examined a phenomenon at the center of these debates: students’ evaluations of academic cheating. Across three studies, we used structured interviews and online surveys to examine first- and third-party judgments and reasoning about cheating events. Third-party scenarios were derived from students’ own accounts of cheating events and manipulated based on the reasons students provided. Findings supported the view that reasoning is central to evaluations of cheating. Participants articulated reasons consistent with their judgments about their own and others’ actions. The findings advance classic debates about reasoning in morality and exemplify a paradigm that can bring further advances.