O'Malley, E, Murphy, JC, McCarthy Persson, U, Gissane, C, and Blake, C. The effects of the Gaelic Athletic Association 15 training program on neuromuscular outcomes in Gaelic football and hurling players: A randomized cluster trial. J Strength Cond Res 31(8): 2119–2130, 2017—Team-based neuromuscular training programs for injury prevention have been tested primarily in female and adolescent athletes in soccer, handball, and basketball with limited research in adult male field sports. This study explored whether the GAA 15, a multifaceted 8-week neuromuscular training program developed by the Gaelic Athletic Association (GAA), could improve risk factors for lower limb injury in male Gaelic footballers and hurlers. Four Gaelic sports collegiate teams were randomized into intervention or control groups. Two teams (n = 41), one football and one hurling, were allocated to the intervention, undertaking a 15 minutes program of neuromuscular training exercises at the start of team training sessions, twice weekly for 8 weeks. Two matched teams (n = 37) acted as controls, participating in usual team training. Lower extremity stability (Y-Balance test [YBT]) and jump-landing technique using the Landing Error Scoring System (LESS) were assessed preintervention and postintervention. There were moderate effect sizes in favor of the intervention for right (d = 0.59) and left (d = 0.69) composite YBT scores, with adjusted mean differences between intervention and control of 3.85 ± 0.91% and 4.34 ± 0.92% for right and left legs, respectively (p < 0.001). There was a greater reduction in the mean LESS score in favor of the intervention group after exercise training (Cohen's d = 0.72, adjusted mean difference 2.49 ± 0.54, p < 0.001). Clinically and statistically significant improvements in dynamic balance and jump-landing technique occurred in collegiate level Gaelic football and hurling players who adopted the GAA 15, when compared with usual training. These findings support application and evaluation of the GAA 15 in other player groups within the Gaelic games playing population.