Peer-assisted learning (PAL) methods have been increasingly integrated into medical education through near-peer, peer-to-peer, and reciprocal-peer tutoring programs.  Tutoring implemented in conjunction with medical school basic science courses have been reported to benefit: medical school administration by addressing large student-to-faculty ratios, tutors by improving teaching and communication skills, and tutees by fostering a welcoming learning atmosphere.  Quantitative studies demonstrated that participation in PAL programs significantly increased tutee examination and course grades, especially for students struggling the most. However, determining the optimal design for a PAL program is difficult as medical schools across the world differ in size, demographic, curriculum design, and resource availability. Thus, a discussion regarding how PAL has been successfully implemented at multiple international institutions, including difficulties and how to overcome them, would be beneficial to identify benefits and challenges of existing programs so they may be optimized in the future.