The efficacy of psychological interventions for children has long been debated among mental health professionals; however, only recently has this issue received national attention, with the U.S. Public Health Service (2000) emphasizing the critical need for early intervention and empirically validated treatments tailored to childrenfs maturational needs.Play therapy is a developmentally responsive intervention widely used by child therapists but often criticized for lacking an adequate research base to support its growing practice.A meta-analysis of 93 controlled outcome studies (published 1953.2000) was conducted to assess the overall efficacy of play therapy and to determine factors that might impact its effectiveness.The overall treatment effect for play therapy interventions was 0.80 standard deviations. Further analysis revealed that effects were more positive for humanistic than for nonhumanistic treatments and that using parents in play therapy produced the largest effects.Play therapy appeared equally effective across age, gender, and presenting issue.