Peer tutoring has become a widely used practice in higher education institutions to support students' academic success, although its effects remain controversial. This article synthesizes 27 independent experimental and quasi-experimental studies to examine the relationship between peer tutoring programs and college students' academic performance, as well as to analyze potential moderating effects based on program or research design features. The findings reveal that peer tutoring programs have a moderate, positive overall effect size (g = 0.480) on college students' academic performance. When considering the heterogeneity of programs, a significantly larger effect size is observed in individualized tutoring, social science and sports science, and studies conducted in Asia. The type of intervention, tutee level, tutoring place, duration, method, measurements, and sample size influence the relationship between peer tutoring programs and students' academic performance, yet these effects are not statistically significant. Consequently, it is recommended that universities develop peer tutoring programs meticulously to enhance their efficiency.