Perivascular adipose tissue (PVAT) plays a crucial, yet underexplored, role in vein remodeling, which occurs after bypass surgery using a venous graft or creation of arteriovenous fistulae for hemodialysis access. PVAT exhibits significant heterogeneity in phenotype and tissue composition depending on the vascular bed, as well as its anatomic location within the vasculature. Through the excretion of adipokines, cytokines, and chemokines, PVAT can shape the vascular response to local and systemic perturbations. Moreover, the active exchange of cells reinforces the bidirectional cross talk between the vessel wall and PVAT. In this review, we describe the role of PVAT in relation to postinterventional vein remodeling, specifically focusing on the effect of surgery on the PVAT phenotype. Moreover, we discuss the pathophysiological mechanisms that ultimately affect clinical outcomes and highlight the therapeutic potential of PVAT to improve vein remodeling.