This study examined how sports intervention may reduce aggressive behaviors in children (Grades 3–6), focusing on the relations between acquisition of self-control skills (SCSs) and aggressive behavior through the mediation of thoughts (i.e., hostility) and emotions (i.e., positive and negative). In a sample of 649 Israeli children, 50% were assigned to an experimental group and the remainder to a waitlisted control group. As hypothesized, children in the experimental group reported significantly larger gains in SCSs and significantly larger decreases in physical aggression, hostile thoughts, and negative emotions.