AbstractWomen with PCOS have substantially greater symptoms of depression and anxiety, and a lower health-related quality of life (HRQoL) compared to women without PCOS. The aim of this study was to determine if high-intensity interval training (HIIT) could provide greater improvements in mental health outcomes than standard moderate-intensity continuous training (MICT). Twenty-nine overweight women with PCOS aged 18–45 years were randomly assigned to 12 weeks of either MICT (60–75% HR_peak, N = 15) or HIIT (> 90% HR_peak, N = 14). Outcome measures included symptoms of depression, anxiety and stress (DASS-21), general HRQoL (SF-36) and PCOS specific HRQoL (PCOSQ) collected at baseline and post-intervention. Reductions in depression (Δ − 1.7, P = 0.005), anxiety (Δ − 3.4, P < 0.001) and stress (Δ − 2.4, P = 0.003) scores were observed in the HIIT group, while MICT only resulted in a reduction in stress scores (Δ − 2.9, P = 0.001). Reductions in anxiety scores were significantly higher in the HIIT group compared to the MICT group (β = − 2.24, P = 0.020). Both HIIT and MICT significantly improved multiple domain scores from the SF-36 and PCOSQ. This study highlights the potential of HIIT for improving mental health and HRQoL in overweight women with PCOS. HIIT may be a viable strategy to reduce symptoms of depression and anxiety in women with PCOS, however, large-scale studies are required to confirm these findings.Trial registration number: ACTRN12615000242527.