<p>The digitalization of higher education has heightened the urgency for universities to address and penalize instances of plagiarism effectively. Previous studies have often relied on surveys to assess students’ attitudes towards plagiarism. However, questionnaires may suffer from social desirability bias and need to oversimplify the complex, context-dependent nature of plagiarism. This study employs a vignette study approach to examine how 2,043 students at a Swiss university assess and sanction hypothetical plagiarism scenarios. We use multilevel regression models and find that personal morality, punitive attitudes, the use of electronic resources, and age are associated with more severe assessments of plagiarism. In contrast, negative peer influence, lack of self-control, and prior engagement in plagiarism negatively affect students’ assessments of the seriousness of plagiarism cases. We find that moral and punitive attitudes, the frequent use of electronic resources, and being male is associated with preferring harsher penalties. Comparisons with academic staff responses (<i>N = </i>766) indicate that although staff take a slightly stricter stance on severity assessments and sanction choices, their overall evaluation pattern remains similar. By examining the factors that shape students’ and staff’s assessments of hypothetical plagiarism cases and their choices of sanctions, our study aims to help universities develop effective antiplagiarism policies that will be perceived as fair and proportionate by both students and academic staff.</p>