A field experiment was conducted to assess the efficacy of a social-support and stress-reduction program intended to influence factors that affect performance anxiety in child athletes. Baseball coaches in an experimental condition received preseason training in which behavioral guidelines for reducing anxiety were presented and modeled. A no-treatment control group did not receive the coach training. Children (N = 152) who played for the two groups of coaches were interviewed and administered sport-specific trait anxiety scales pre- and postseason. A manipulation check demonstrated that trained coaches differed from controls in player-perceived behaviors in accordance with the goals of the intervention. They were also evaluated more positively by their players, their players reported having more fun, and their teams exhibited a higher level of attraction among players despite the fact that they did not differ from controls in won-lost records. Consistent with theory-based predictions, the intervention program significantly reduced children's trait anxiety over the course of the season.