College students' need for mental health care has increased dramatically, leaving campus counseling and mental health centers struggling to meet the demand. This has led to the investigation and development of extra-center, population-based interventions. Student-to-student support programs are but one example. Students themselves are a plentiful, often-untapped resource that extends the reach of mental health services on campus. Student-to-student programs capitalize on students' natural inclination to assist their peers. A brief review of the prevalence and effects of mental disorders in the college population is provided, followed by a broad overview of the range of peer-to-peer programs that can be available on college campuses. Two innovative programs are highlighted: (1) a hospital- and community-based program, the College Mental Health Program (CMHP) at McLean Hospital, and 2) the Student Support Network (SSN) at Worcester Polytechnic Institute. The subsequent section reviews the literature on peer-to-peer programs for students with serious and persistent mental illness for which there is a small but generally positive body of research. This lack of an empirical basis in college mental health leads the authors to argue for development of broad practice-research networks.