Ovarian cancer (OC) is the most important cause of gynecological cancer-related mortality, with the majority of women presenting with advanced disease. Although surgery and chemotherapy can improve survival, the 5-year survival rates remain ominously low at 45%. Novel therapies are urgently needed. The presence of T cells in the OC tumor microenvironment is correlated with improved progression-free and overall survival, while the presence of regulatory T cells and expression of T-cell inhibitory molecules is correlated with a poor prognosis. These data indicate that immunotherapy could hold promise in improving the treatment of OC. In this review, we will discuss the rational of immunotherapy, highlight current results with cancer vaccines, adoptive T-cell therapy and immunomodulatory agents and summarize the immune effects of selected chemotherapeutic and radiotherapeutic agents.