Students taking developmental mathematics often need academic support to succeed in their courses, but also benefit from support in adapting to university life. In this paper we describe our experience in developing, implementing, and evaluating a peer mentoring program for developmental mathematics students at a large research university that focused on both academic and psychosocial support. We give a summary of the success and persistence rates of students in the program, compare them to nonmentored students, and discuss the results of an assessment of the project that includes student feedback and lessons learned.