The crosstalk between cancer cells and host cells is a crucial prerequisite for tumor growth and progression. The cells from both the innate and adaptive immune systems enter into a perverse relationship with tumor cells to create a tumor-promoting and immunosuppressive tumor microenvironment (TME). Epithelial ovarian cancer (EOC), the most lethal of all gynecological malignancies, is characterized by a unique TME that paves the way to the formation of metastasis and mediates therapy resistance through the deregulation of immune surveillance. A characteristic feature of the ovarian cancer TME is the ascites/peritoneal fluid, a malignancy-associated effusion occurring at more advanced stages, which enables the peritoneal dissemination of tumor cells and the formation of metastasis. The standard therapy for EOC involves a combination of debulking surgery and platinum-based chemotherapy. However, most patients experience disease recurrence. New therapeutic strategies are needed to improve the prognosis of patients with advanced EOC. Harnessing the body’s natural immune defenses against cancer in the form of immunotherapy is emerging as an innovative treatment strategy. NK cells have attracted attention as a promising cancer immunotherapeutic target due to their ability to kill malignant cells and avoid healthy cells. Here, we will discuss the recent advances in the clinical application of NK cell immunotherapy in EOC.