Polycystic ovary syndrome (PCOS) is a very common condition affecting 4% to 18% of women. Being overweight worsens all clinical features of PCOS. These clinical features include reproductive manifestations such as reduced frequency of ovulation and irregular menstrual cycles, reduced fertility, polycystic ovaries on ultrasound, and high male hormones such as testosterone which can cause excess facial or body hair growth and acne. PCOS is also associated with metabolic features and diabetes and cardiovascular disease risk factors including high levels of insulin or insulin resistance and abnormal cholesterol levels. PCOS affects quality of life and can worsen anxiety and depression either due to the features of PCOS or due to the diagnosis of a chronic disease. A healthy lifestyle consists of a healthy diet, regular exercise and achieving and maintaining a healthy weight. This review identified six studies with 164 participants that assessed the effects of a healthy lifestyle in women with PCOS. In this review, there were no studies reporting on fertility outcomes such as pregnancy, live birth and miscarriage. While some studies reported on menstrual regularity and ovulation, the findings were reported in a variety of ways and it was not possible to estimate the overall effects of lifestyle on these outcomes. Current evidence suggests that following a healthy lifestyle reduces body weight and abdominal fat, reduces testosterone and improves both hair growth, and improves insulin resistance. There was no evidence that a healthy lifestyle improved cholesterol or glucose levels in women with PCOS.