This article takes a dual focus on the theme of student formative peer assessment. On the one hand it offers a thorough literature review in this field, while on the other it unpacks a case study of curriculum design where peer assessment has been adopted. The practical example draws on recent changes made to a third- and final-year undergraduate research dissertation course in a UK architectural school. Although peer assessment worked quite well in this small setting, similar findings might be uncovered when scaled up to larger cohorts, as well as other disciplines and year groups. The research findings are certainly relevant for other contexts. Qualitative research from a focus group with six students on the course informs the empirical body of the paper. Through engaging with students' reflections, as well as the relevant literature, and reflexively looking at the curriculum changes, this paper discusses some of the benefits and drawbacks that can arise from peer assessment in this context. Peer assessment is not without its challenges and hiccups, but, despite these, the benefit to autonomous critical thinking cannot be understated. And arguably peer assessment is especially germane for final-year undergraduates as they embark on employment or more advanced studies.