Ubiquitin specific peptidase 11 (USP11) is a deubiquitinating enzyme (DUB) and has been observed to promote mammary tumor initiation and progression. Several reports have shown that USP11 plays an important role in cancer development. Previous research has shown that USP11 is upregulated in breast cancer, but the function of USP11 in ovarian cancer has not been determined to date. In the present study, we observed that USP11 was upregulated in ovarian cancer tissues and cell lines. To determine the role of USP11 in ovarian cancer, we performed several functional experiments, including Transwell migration and invasion analysis, in vitro and in vivo deubiquitination assays, colony formation assays, and CCK‑8 assays. Notably, we observed that USP11 facilitated the epithelial‑to‑mesenchymal transition (EMT), which is an important process in cancer cell invasion and metastasis. Furthermore, we observed that USP11 regulated EMT through the regulation of Snail. Our results revealed that USP11 promoted EMT in ovarian cancer by deubiquitinating Snail, and USP11 may be a novel therapeutic target for ovarian cancer treatment.