Circular RNAs (circRNAs) play a role in various types of cancer. The present study suggested that hsa_ circ_0026123 expression was upregulated in ovarian cancer (OVA), which was associated with its role in OVA. However, the role of hsa_circ_0026123 in OVA cell invasion and proliferation remains unclear. In the present study, OVA tissues and cell lines were used to investigate the functions of hsa_circ_0026123. The associations between hsa_circ_0026123, miR-124-3p and enhancer of zeste homolog 2 (EZH2) were examined using a luciferase reporter assay. RT-qPCR and western blot analysis were used for gene and protein expression analysis, respectively. Tumor growth was detected using nude mouse tumor xenografts derived from SKOV3 cells, with or without hsa_circ_0026123 downregulation. The results confirmed that hsa_circ_0026123 expression was upregulated in OVA tissues and cell lines, while hsa_circ_0026123 silencing suppressed cell proliferation and migration; it also suppressed the expression of cancer stem cell (CSC) differentiation-related markers in either in vivoor in vitro experiments. The data revealed that hsa_circ_0026123 downregulation suppressed EZH2 expression by miR-124-3p 'sponging', which was confirmed by rescue experiments and luciferase reporter assays. The results revealed that hsa_circ_0026123 silencing suppressed ovarian cancer cell progression via the miR-124-3p/EZH2 signaling pathway. Overall, the findings demonstrated that hsa_circ_0026123 knockdown inhibited OVA cell progression by regulating the miR-124-3p/EZH2 axis. This methodology may thus be used for the targeted therapy of OVA, as well as a candidate biomarker for the diagnosis and treatment of OVA.