Transforming growth factor-alpha (TGFA) has been shown to play a role in experimental chronic kidney disease (CKD) associated with nephron reduction, while its role in diabetic kidney disease (DKD) is unknown. We have previously reported the development of a neutralizing antibody to human/mouse TGFA. This antibody was used to determine the role of TGFA in two models of renal disease, the remnant surgical reduction model and the uninephrectomized (uniNx) db/db DKD model. In addition, the role of TGFA in driving DKD was examined using an AAV approach to overexpress TGFA in a DKD model. In vivo blockade of TGFA attenuated kidney disease progression in both non-diabetic 129S6 nephron reduction and type 2 diabetic uniNx db/db models, whereas overexpression of TGFA in uniNx db/db model accelerated renal disease. Therapeutic activity of the TGFA antibody was enhanced with renin angiotensin system (RAS) inhibition with further improvement in renal parameters. In addition, we determined that urine and serum TGFA are increased in human DKD. These findings suggest a pathologic role for TGFA in DKD and support the possibility that therapeutic administration of neutralizing antibodies could provide a novel treatment for the disease.