Background Epithelial ovarian cancer (EOC) ranks as the most lethal of gynecological cancers. Despite advances in therapeutic interventions that have marginally extended survival rates, the early detection and management of EOC pose significant hurdles. Consequently, identifying novel therapeutic targets is imperative for enhancing the survival outcomes of patients afflicted with this malignancy. Purpose This research is aimed at exploring the functions of Bone Marrow Stromal Antigen 2 (BST2) in the pathogenesis of EOC and their influence on macrophage polarization, evaluating their viability as targets for immunotherapy. Methods Gene expression profiles and clinical data of EOC patients were retrieved from the TCGA repository to develop prognostic models centered on BST2. The expression patterns of BST2 in HGSOC cell lines were quantified via RT‐qPCR and Western blot analyses. The impact of BST2 on the proliferative, migratory, and invasive capacities of EOC cells was assessed through gene silencing and gene overexpression experiments. Results Elevated levels of BST2 expression were observed in EOC tissues, correlating with adverse prognostic indicators. Enhanced BST2 expression facilitated EOC cell growth, motility, and invasiveness, whereas BST2 suppression mitigated these oncogenic attributes. In vivo assessments revealed that BST2 augmentation modified the macrophage phenotypes within grafted ovarian tumors, with BST2 diminution reversing these effects. Conclusion The findings propose that BST2 acts as a pivotal facilitator in the progression of ovarian carcinoma. The expression metrics of BST2 may serve as prognostic markers for patient outcomes in EOC. These findings suggest that BST2 is a key promoter of ovarian cancer progression, and its expression may serve as a prognostic marker. The mechanisms uncovered, including the modulation of macrophage polarization and neural marker expression, indicate that targeting BST2 represents a potential future strategy for immunotherapy in EOC.