The authors assessed the impact of peer review on student writing in four sections of an undergraduate Developmental Psychology course. They hypothesized that peer review would result in better writing in the peer review group compared to the group with no peer review. Writing was rated independently by two instructors who were blind to the conditions. The results showed a pattern opposite to this hypothesis, with the no-peer review group performing significantly better than the peer review group. This enhancement in the performance of the no-peer review group was reminiscent of the Hawthorne effect. Surveys also were obtained from both groups regarding their perceptions about the process and use of different tools (for example, informal peer review and writing centers). Implications for the future use of peer review in writing among undergraduates are discussed.