BACKGROUND: Polycystic ovary syndrome (PCOS) is the most common ovarian dysfunction. Recent studies showed the effectiveness of licorice on metabolic profiles with inconsistent findings. So, we investigated the effect of licorice on obesity indices, glycemic indices, and lipid profiles in women with PCOS. METHODS: This randomized, double-blind, placebo-controlled trial was performed on 66 overweight/obese women with PCOS. The participants were randomly assigned to receive either 1.5 gr/day licorice extract plus a low-calorie diet (n = 33) or placebo plus a low-calorie diet (n = 33) for 8 weeks. Participants' anthropometric indices and body composition were assessed using standard protocols. Fasting blood sugar (FBS), insulin levels, low-density lipoprotein-cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG), and high-density lipoprotein-cholesterol (HDL-C) were measured using enzymatic kits. The homeostasis model assessment-insulin resistance (HOMA-IR) and HOMA of β-cell function (HOMA-B) were calculated using valid formulas. RESULTS: Between-group comparisons demonstrated significant differences between the groups in terms of obesity indices (body weight, BMI, and body fat), lipid profiles (TG, TC, LDL-C, and HDL-C), FBS and insulin levels, HOMA-IR, and HOMA-B at the end of the study (P < 0.05). Supplementation with licorice plus a low-calorie diet was also more effective in improving all parameters than a low-calorie diet alone after adjusting for confounders (baseline values, age, weight changes, and physical activity changes) (P < 0.05). CONCLUSION: The findings showed that licorice consumption leads to improvements in obesity indices, glucose homeostasis, and lipid profiles compared to placebo. Due to possible limitations of the study, further research is needed to confirm these findings.