The immune microenvironment plays a pivotal role in maintaining ovarian homeostasis. Polycystic ovary syndrome (PCOS), a common endocrine and metabolic disorder, is closely associated with immune microenvironment imbalance. This review systematically describes the dysregulation of innate immune cells (e.g., macrophages, natural killer cells and dendritic cells) and adaptive immune cells (e.g., Th1, Th2, Treg and Th17) in PCOS, highlighting their impacts on ovarian function, insulin resistance, and hyperandrogenemia. These findings underscore the central role of immune microenvironment disturbances in PCOS pathogenesis. Additionally, the association between gut microbiota dysbiosis and PCOS is explored, emphasizing how gut microbiota influences metabolic byproducts and hormonal levels to contribute to PCOS development. Furthermore, therapeutic strategies targeting immune microenvironment imbalance such as modulating macrophage polarization, restoring Th1/Th2 and Th17/Treg balance, and ameliorating gut microbiota dysbiosis are discussed, offering novel insights for PCOS immunotherapy. In conclusion, this review comprehensively analyzes the pathogenesis of PCOS from the perspective of the immune microenvironment, aiming to provide a theoretical foundation and reference for future research and clinical practice.