Epithelial ovarian carcinoma poses a significant challenge due to its resistance to chemotherapy and propensity for metastasis, thereby reducing the effectiveness of conventional treatments. Hence, the identification of novel compounds capable of augmenting the anti-cancer efficacy of platinum-based chemotherapy is imperative. Oxyresveratrol (OXY), a derivative of resveratrol, has been demonstrated to possess antiproliferative and apoptosis-inducing effects across various cancer cell lines. Notably, OXY appears to exert its effects by inhibiting the PI3K/AKT/mTOR signaling pathway. However, the synergistic potential of OXY in combination with cisplatin against epithelial ovarian cancer has not yet been elucidated. The current study investigated the synergistic effects of OXY and cisplatin on the ovarian cancer cell lines SKOV3 and TOV21G. We found that OXY significantly enhanced cisplatin's ability to reduce cell viability, induce apoptosis, induce cell cycle arrest, and increase the proportion of cells in the sub-G1 phase. Furthermore, OXY treatment alone dose-dependently inhibited the production of anti-apoptotic proteins including Mcl-1, Bcl-xL, and XIAP under EGF activation. Mechanistically, OXY suppressed the PI3K/AKT/mTOR signaling pathway by reducing phosphorylated AKT, while having no discernible effect on the MAPK pathway. These findings highlight OXY's potential to enhance ovarian cancer cell sensitivity to chemotherapy, suggesting its development as a pharmaceutical adjunct for clinical use in combination therapies.