Many residencies whose trainees care for a growing population of older adults lack formal geriatrics education. Despite this, trainee physicians from a diverse range of specialties must learn to communicate and collaborate with each other to provide high-quality care for older adults. To address this need, we designed, implemented, and assessed a novel peer teaching exchange between a geriatrics fellowship and four residency programs.A geriatrics fellowship invited residents from dermatology, physical medicine and rehabilitation, anesthesiology, and interventional radiology to teach a session about their specialty at the geriatric fellowship's didactics. In exchange, geriatrics fellows taught sessions for the participating residencies about caring for older adults.Urban academic center.Trainees were geriatrics fellows and residents from the four collaborating training programs who participated in the peer teaching exchange.We collected quantitative and qualitative data to assess learner attitudes and self-efficacy following the peer-taught sessions.We organized eight peer-taught sessions attended by a collective total of 74 trainees. Overall, 85% of learners at the geriatric didactics completed a pre- and postsurvey following the specialty resident-led session. Trainees demonstrated significant improvements in self-efficacy regarding consulting and communicating with specialist colleagues following the sessions. A total of 95% of specialty residents attending the talks led by geriatrics fellows completed open-ended qualitative feedback forms. Residents identified frailty and medication optimization as new areas of learning.This novel teaching modality represents a promising tool for increasing medical knowledge across specialties and facilitating collaboration and communication at the trainee level.