Background <p>Renal fibrosis is the common outcome of chronic renal disease. Currently, there are no effective therapies. Fibroblast activation and extracellular matrix accumulation are key processes driving renal fibrosis.</p> Methods and results <p>Fibroblast activation protein (FAP) is highly induced in injured kidneys, and immunofluorescence staining revealed that FAP is mainly expressed in Platelet-derived growth factor receptor-beta (PDGFRβ)⁺ and alpha-smooth muscle actin (α-SMA)⁺ myofibroblasts in kidney samples from mice with renal fibrosis and patients with chronic kidney diseases or post-acute kidney injury. In this study, targeting FAP as a strategy for treating renal fibrosis is tested using two preclinical animal models: the mouse models of unilateral ureteral obstruction and unilateral renal ischemia–reperfusion. Adoptive transfer of T cells expressing chimeric antigen receptor specific to FAP or administration of an FAP inhibitor (SP-13786) significantly alleviated kidney fibrosis in both mouse models. Eliminating FAP⁺ fibroblasts using chimeric antigen receptor T-cell (CAR-T) therapy or inhibiting the FAP prevented fibroblast overactivation, proliferation, and migration, promoted apoptosis, and effectively suppressed other myofibroblast populations.</p> Conclusions <p>Overall, we report herein that targeting FAP offers a novel promising treatment approach for renal fibrosis.</p> Graphical abstract <p></p>