ObjectiveThis meta-analysis estimated the population effect size for Pilates effects on mental health outcomes. Data sourcesArticles published prior to August 2017 were located with searches of Pubmed, Medline, Cinahl, SportDiscus, Science Direct, PsychINFO, Web of Science, and Cochrane Controlled Trial Register using combinations of: Pilates, Pilates method, mental health, anxiety, and depression. Study selectionEight English-language publications that included allocation to a Pilates intervention or non-active control and a measure of anxiety and/or depressive symptoms at baseline and after the Pilates intervention were selected. Data extractionParticipant and intervention characteristics, anxiety and depressive symptoms and other mental health outcomes, including feelings of energy and fatigue and quality of life, were extracted. Hedges’ d effect sizes were computed, study quality was assessed, and random effects models estimated sampling error and population variance. Data synthesisPilates resulted in significant, large, heterogeneous reductions in depressive (Δ = 1.27, 95%CI: 0.44, 2.09; z = 3.02, p ≤ 0.003; N = 6, n = 261) and anxiety symptoms (Δ = 1.29, 95%CI: 0.24, 2.33; z = 2.40, p ≤ 0.02; N = 5, n = 231) and feelings of fatigue (Δ = 0.93, 95%CI: 0.21, 1.66; z = 2.52, p ≤ 0.012; N = 3, n = 161), and increases in feelings of energy (Δ = 1.49, 95%CI: 0.67, 2.30; z = 3.57, p < 0.001; N = 2, n = 116). ConclusionsThough this review included a small number of controlled trials with small sample sizes and non-active control conditions of variable quality, the available evidence reviewed here supports that Pilates improves mental health outcomes. Rigorously designed randomized controlled trials, including those that compare Pilates to other empirically-supported therapies, are needed to better understand Pilates’ clinical effectiveness and plausible mechanisms of effects.