Metastasis is the most common cause of death in ovarian cancer patients but remains largely untreated. Epithelial‑mesenchymal transition (EMT) is critical for the conversion of early‑stage ovarian tumors into metastatic malignancies. Thus, investigating the signaling pathways promoting EMT may identify potential targets for the treatment of metastatic ovarian cancer. Lysine demethylase 2A (KDM2A), also known as FBXL11 and JHDM1A, is a histone H3 lysine 36 (H3K36) demethylase that regulates EMT and the metastasis of ovarian cancer. However, the function and underlying mechanisms of EMT suppression in ovarian cancer have not been thoroughly elucidated to date. In the present study, we used Gene Expression Omnibus (GEO) databases to determine that KDM2A is significantly upregulated in human ovarian cancers. KDM2A expression was assessed by immunohistochemistry of epithelial ovarian cancer (EOC) borderline ovarian tumors and normal ovary tissues. Seven fresh EOC tissues and 3 fresh normal ovary tissues were collected for western blot analysis. Kaplan‑Meier survival curves were constructed to identify genes related to EOC prognosis from the TCGA data portal. Stable KDM2A‑knockdown cell lines were established to study the biological functions and underlying mechanisms of KDM2A in EMT in vitro. GEO database analysis revealed that KDM2A was highly upregulated in EOC tissues; this analysis was accompanied by immunochemistry and western blot analysis using samples of human tissues. High expression of KDM2A was associated with poor survival in EOC patients. KDM2A knockdown promoted apoptosis and suppressed the proliferation, migration and invasion of tumor cells in vitro. EMT and the PI3K/AKT/mTOR signaling pathway were suppressed in KDM2A‑silenced cells. Inactivation of the PI3K/AKT/mTOR signaling pathway in A2780 cells induced EMT inhibition. Our data revealed that KDM2A functions as a tumor oncogene, and the downregulation of KDM2A expression regulates EMT and EOC progression, providing a valuable prognostic marker and potential target for the treatment of EOC patients.