Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-age women. This systematic review, meta-analysis, and meta-regression aims to compare the effect of insulin sensitizer pharmacotherapy on metabolic and reproductive outcomes in women with PCOS and overweight or obesity. We searched online databases MEDLINE via OVID, EMBASE, Clinicaltrials.gov, and EudraCT for trials published from inception to November 13, 2023. Inclusion criteria were double-blind, randomized controlled trials in women diagnosed with PCOS, body mass index (BMI) ≥ 25 kg/m2, which reported metabolic or reproductive outcomes. The intervention was insulin sensitization pharmacotherapy versus placebo or other agents. The primary outcomes were changes from baseline BMI, fasting blood glucose, and menstrual frequency. Nineteen studies were included in this review. Metformin had the most significant effect on the fasting plasma glucose and body mass index. Insulin sensitizer pharmacotherapy significantly reduced fasting plasma glucose, body mass index, fasting serum insulin, HOMA-IR, sex hormone binding globulin, and total testosterone, but the effect size was small. There was a lack of menstrual frequency and live birth data. The results indicate a role for insulin sensitizers in improving the metabolic and, to a lesser degree, reproductive profile in these women. Further research should examine insulin sensitizers' effects on objective measures of fecundity.