Blockading programmed death ligand 1 (PD-L1) shows promising results in patients with some cancers, but not in those with ovarian cancer. V-domain Ig suppressor of T cell activation (VISTA) is a recently discovered immune checkpoint protein that suppresses T cell activation. This study aimed to investigate the expression and clinical significance of VISTA in ovarian cancer as well as its relationship with PD-L1. VISTA and PD-L1 levels in 146 ovarian cancer samples were assessed using immunohistochemistry. We investigated the association between VISTA and other clinicopathological variables, including survival. The associations between the VISTA-encoding C10orf54 gene, other immune checkpoints, and survival were analyzed. VISTA was detected in 51.4% of all samples and 46.6% of PD-L1-negative samples; it was expressed in 28.8%, 35.6%, and 4.1% of tumor cells (TCs), immune cells (ICs), and endothelial cells, respectively. Furthermore, VISTA expression was associated with pathologic type and PD-L1 expression. Moreover, VISTA expression in TCs, but not in ICs, was associated with prolonged progression-free and overall survival in patients with high-grade serous ovarian cancer. The expression of C10orf54 mRNA was associated with prolonged overall survival and immune escape-modulating genes. These results showed that VISTA expression in ovarian tumor cells was associated with a favorable prognosis in patients with high-grade serous ovarian cancer; however, additional studies are required to better understand the expression and role of VISTA in ovarian cancer. Keywords Ovarian cancer • PD-L1 • VISTA • Immune checkpoints • Prognosis Abbreviations CTLA4 Cytotoxic T-lymphocyte-associated protein 4 FIGO International federation of gynecology and obstetrics HGSOC High-grade serous ovarian carcinoma IC Immune cell LAG3 Lymphocyte activation gene-3 TCGA The cancer genome atlas TC Tumor cell TIGIT T cell immunoreceptor with Ig and ITIM domains TIM-3 T cell immunoglobulin and mucin domain-3 TMA Tumor tissue microarray VISTA V-domain Ig suppressor of T cell activation Electronic supplementary material The online version of this article (