This article reports a systematic review of the effectiveness of individual child play therapy with children aged 4–12 on several different presenting concerns. From over 5,000 citations, 180 studies were reviewed in detail and 17 met the inclusion criteria. A wide range of results on different concerns were revealed, with effect sizes ranging from d = –0.04 to g = 3.63, though most ranged from .35 to .80. Across most concerns, play therapy was affirmed as an empirically supported therapy.