This article presents findings from a meta-analysis of 24 primary research studies on the Second Step social emotional learning program. Program content knowledge, outcomes related to prosociality, and outcomes related to antisociality are examined as outcome categories in randomized controlled trials, quasi-experimental studies and, separately, single-group repeated measures design studies. Students participating in Second Step demonstrated increased knowledge of program content and increased prosocial outcomes. Participation in the program was not associated with significant changes in antisocial outcomes. Evidence suggests the possibility of publication bias in studies reporting knowledge outcomes but no evidence of publication bias in studies reporting prosocial and antisocial outcomes. This study complements broader meta-analyses on SEL programs and aims to inform local decision making by providing an estimate of the overall effects of the Second Step program on a variety of student outcomes.