This article considers the impact of a student peer-mentoring programme (the Mentor Accountant Project, MAP) on first-year undergraduates' academic performance. The development of MAP was informed by reference to extant literature; it relies on the voluntary services of third-year students who then act as mentors to first-year student mentees in an undergraduate degree programme. The impact of MAP in two Scottish universities is measured by reference to the changes in the approaches to learning and the academic achievement of two groups of students: those who participated in MAP and those who did not. The findings indicate that those first-year students who participated in MAP did not experience the significant decline in their deep and strategic approaches to learning that their non-MAP peers did. Likewise, those first-year students who participated in MAP demonstrated a stronger academic performance in comparison to their non-MAP equivalents. In addition, the MAP scheme appeared to have little impact on the approaches to learning of the third-year participants; and the academic performance of the third-year MAP participants was indistinguishable from that of their non-MAP counterparts. The evidence suggests that participation in MAP is beneficial for first-year students.