There is a growing body of evidence suggesting a link between sport participation and violent behavior outside of the sporting context. However, there have been few studies that have investigated the basis of this relationship. The current study examined longitudinal relationships between sport participation, problem alcohol use, and various violent behaviors, and whether sport participation moderates relationships between problem alcohol use and violence. The sample comprised 2,262 young adults (55% female, age range at Time 1 = 17-24 years) from Victoria, Australia, surveyed in 2010 and 2012. When controlling for common risk factors, substance use, and past violence, sport participation was not associated with any violent behaviors 2 years later. However, sport participation moderated the relationship between problem alcohol use and fighting, whereby problem alcohol use was associated with engaging in fights 2 years later for sport participants, but not for nonparticipants. These findings suggest that it is not sport participation per se that influences later violence but the drinking norms or culture embedded within certain sporting contexts. Prevention approaches that address the drinking culture and social approval of excessive alcohol consumption within sporting contexts may reduce the incidence of violent behavior in the community.