Groupwork is a crucial aspect of work contexts and a key twenty first century skill. Assessment of groupwork provides a persistent challenge for educators in university contexts with students reporting experiences of unfairness from their peers during groupwork. This study developed a novel Peer Assessment Fairness Instrument to explore factors driving students' perceptions of fairness during groupwork processes. The results showed that students perceived fairness of groupwork in relation to (1) the grading outcomes they received (i.e. grade congruence), (2) the procedures based on which groups contributed to groupwork (i.e. performative group dynamics), and (3) the relationships based on which group members interacted (i.e. interpersonal treatment). The findings provide student-driven directions to promoting fairer peer assessments within groupwork contexts.