Teaching near-peers yields numerous benefits to residents. Opportunities for near-peer teaching are typically restricted to hospital settings. Little is known about the educational potential of outpatient near-peer teaching. To describe Primary Care Teaching (PC Teach), a novel outpatient near-peer teaching experience for residents in a large, urban, internal medicine residency program; characterize its feasibility and acceptability; and evaluate changes in residents' self-reported confidence in outpatient teaching and attitudes toward teaching and primary care/outpatient medicine. In 2020-2021, following a didactic workshop, 43 postgraduate year 3 (PGY-3) residents at continuity clinics assigned to PC Teach completed a series of half-day sessions acting as preceptor to interns under attending supervision. Worksheets facilitated post-session feedback for residents and interns. Eighteen PGY-3s at nonparticipating clinics, who also completed the workshop, served as controls. We assessed process measures for feasibility and acceptability and analyzed resident attitudes using pre-post surveys. Participating residents completed 2 to 8 sessions each. Post-intervention scores for confidence in outpatient teaching and attitudes toward teaching were greater, relative to pre-intervention group means, for intervention residents (median pre-post changes +0.60 [IQR 0.26, 1.26] and +0.46 [-0.04, 0.46], respectively) vs controls (-0.15 [-0.48, 0.85] and -0.36 [-0.86, 0.39]; between-group differences +0.75 [P=.03] and +0.82 [P=.02]). Changes in attitudes toward primary care/outpatient medicine did not differ significantly between intervention and control groups (+0.43 [-0.07, 0.68] and 0.04 [-0.58, 0.42]; between-group difference +0.39 [P=.12]). In multivariable analyses, odds of gains in confidence in outpatient teaching remained significantly larger for intervention residents vs controls. Implementing PC Teach with existing resources was feasible and acceptable, with program flexibility highlighted as a strength. Resident participation was associated with greater confidence in outpatient teaching.