Background: The number of autistic individuals attending college or university is increasing, yet graduation rates are low as postsecondary environments often fail to support autistic students' individual needs. Peer mentorship programs are emerging as a promising approach for providing individualized, one-on-one support to meet this service gap for autistic postsecondary students. However, no literature has systematically described these programs. Methods: We conducted a systematic review that described existing peer mentorship programs for autistic students in postsecondary education as well as their effectiveness. Results: Our search of five databases found nine unique programs that were evaluated in 11 peer-reviewed articles. Programs reported positive outcomes in various domains, which included social skills, academic performance, and sense of belonging. The evidence for these programs was primarily qualitative, sample sizes were small, and there was considerable heterogeneity in the format, provision, and goals of these programs, as well as the evaluation methods used. Conclusions: Overall, the state of the research related to the efficacy of peer mentorship programs for autistic students remains in its infancy, and further research is needed to quantify effectiveness and enable program comparisons.