Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting 4 to 18 % of reproductive-aged women with reproductive, metabolic and psychological co-morbidities. Lifestyle management (diet, physical activity and behavioural advice) is the first-line treatment for PCOS according to NHMRC-approved guidelines. This study aimed to update a previous Cochrane review which assessed the effectiveness of lifestyle treatment in improving reproductive, anthropometric, metabolic and quality of life factors in PCOS. Electronic databases (e.g. MEDLINE, EMBASE, PsycINFO etc), clinical trial registries and grey literature databases were searched. Fourteen studies were included with n=682 participants. Four studies compared combined dietary, exercise and behavioural interventions to minimal intervention while ten studies involved exercise only. Risk of bias varied with 7/14 having adequate sequence generation and clinician or outcome assessor blinding and 6/14 having adequate allocation concealment, complete outcome data and being free of selective reporting. There were no studies assessing the fertility primary outcomes of pregnancy, live birth and miscarriage. Lifestyle intervention provided benefits when compared to minimal treatment for secondary reproductive, anthropometric and reproductive outcomes. These included endpoint values for total testosterone (mean difference (MD) -0.17 nmol/L, 95% confidence interval (CI) -0.31 to -0.02), hirsutism or excess hair growth by the Ferriman-Gallwey score (MD -1.19, 95% CI -2.35 to -0.03), weight (MD -2.91 kg, 95% CI -4.20 to -1.63), waist circumference (MD -1.88 cm, 95% CI -3.23 to -0.53), fasting insulin (MD -1.96 µU/mL, 95% CI -2.78 to -1.14), total cholesterol (MD -0.21 mmol/L, 95% CI -0.33 to -0.09), low-density lipoprotein cholesterol (MD -0.35 mmol/L, 95% CI -0.48 to -0.22), high density lipoprotein cholesterol (MD 0.09, 95% CI 0.06 to 0.13) and quality of life (MD 0.39, 95%CI 0.16 to 0.61). Lifestyle intervention improves body weight, hyperandrogenism (high male hormones and clinical effects), cholesterol levels and insulin resistance in women with PCOS.