As they navigate academic life, students must decide whether the acts of copying they encounter constitute plagiarism, and whether those acts are wrong. The present study investigated students' perceptions, evaluations, and reasoning about copying. In interviews about hypothetical scenarios involving copying, undergraduates (N = 60) reported whether the characters' actions constituted plagiarism, whether the actions were wrong, and why. Students' perceptions varied depending on textual similarity and type of academic task. When students perceived an act as plagiarism, they almost always believed it was wrong. In explaining their evaluations of plagiarism, students commonly referenced concerns about "learning consequences," "rules," and "fairness." As expected, most students expressed uncertainty about what constitutes plagiarism and whether copying was wrong. The findings validate a new method and highlight the need for a situated theoretical model of decision-making that goes beyond stable characteristics and incorporates perceptions, evaluations, and reasoning about specific texts and contexts.