Aim: Previous observations have implicated miR-509-3p's ability in regulating cisplatin-triggered apoptosis in ovarian cancer. However, the underlying mechanisms were not fully understood. Materials & methods: The roles of miR-509-3p in cellular apoptosis were assessed through MTT and DAPI assays. The confirmation of the regulation of BCL2 family members by miR-509-3p was investigated by luciferase reporter assay, western blot, quantitative real-time PCR and rescue experiments. Results: MiR-509-3p can decrease the IC₅₀ values of cisplatin and promote apoptosis in ovarian cancer cells. Furthermore, on a panel of anti-apoptotic proteins, we identified that miR-509-3p could regulate BCL2, BCL2L2 and MCL1 via their 3′UTRs. Conclusion: Our study demonstrates that miR-509-3p could sensitize ovarian cancer cells to cisplatin treatment by targeting multiple anti-apoptosis genes including BCL2.