Eukaryotic initiation factor 4A-3 (EIF4A3) is a key component of the exon junction complex (EJC) and is extensively involved in RNA splicing, inducing mRNA decay, and regulating the cell cycle and apoptosis. However, the potential role of EIF4A3 in EC has not been comprehensively investigated and remains unknown. Here, we report that the expression level of EIF4A3 is dramatically elevated in endometrial cancer (EC) samples compared with normal EC samples via bioinformatics analysis and immunohistochemistry analysis, and that high expression of EIF4A3 promotes the proliferation, migration, and invasion of EC cells. Mechanistically, we found that high EIF4A3 expression stabilized cell division cyclin 20 (CDC20) mRNA, and high EIF4A3 expression induced pro-carcinogenic effects in EC cells that were efficiently antagonized upon knockdown of CDC20, as well as Apcin, an inhibitor of CDC20. These findings reveal a novel mechanism by which high expression of EIF4A3 induces CDC20 upregulation, thus leading to EC tumorigenesis and metastasis, indicating a potential treatment strategy for EC patients with high EIF4A3 expression using Apcin. KEY MESSAGES: The expression level of EIF4A3 was dramatically elevated in endometrial cancer (EC) samples compared with normal endometrial cancer samples. High EIF4A3 expression stabilized CDC20 mRNA, and high EIF4A3 expression induced pro-carcinogenic effect in EC cells which was efficiently antagonized upon knockdown of CDC20. Apcin, an inhibitor of CDC20, could effectively counteract high expression of EIF4A3 inducing EC tumourigenesis and metastasis, indicating the potential treatment strategy for EC patients with EIF4A3 high expression by using Apcin.