Numerous studies have examined the relationship between social support and prosocial behavior and have concluded that social support is an important factor in generating prosocial behavior. However, different studies have produced different conclusions, and the moderating effect on the relationship is not entirely clear. The current study uses a three‐level meta‐analysis method to clarify the relationship between social support and prosocial behavior, and explores the moderating variables that affect the relationship between the two variables. Through a systematic literature search, a total of 92 studies, 418 effect sizes, and 74,378 participants were obtained. The main effects test found a significant positive correlation between social support and prosocial behavior. Tests of the moderating effects indicated that the relationship between social support and prosocial behavior was moderated by year of publication, source of social support, measurement of social support and measurement of prosocial behavior. In summary, social support plays an important role in prosocial behavior, and exploring their relationship is beneficial to families, schools and society in guiding individuals' prosocial behavior.