The A3 adenosine receptor (A₃AR) is increasingly recognized as a potent therapeutic target in diverse diseases, yet its specific contribution to chronic kidney disease (CKD) progression requires further investigation. Here, we identified a marked upregulation of A₃AR in CKD kidneys, a change that inversely correlated with kidney function. Interestingly, our in vivo models demonstrated that although A₃AR classically functions as a Gi-coupled receptor to reduce cAMP, its kidney injury-driven upregulation paradoxically triggered the PKA-CREB pathway. Subsequent mechanistic studies revealed that A₃AR contributes to kidney fibrosis via non-canonical pathways, specifically by engaging the MAPK-MSK1-CREB pathway and enhancing TGF-β-dependent SMAD and PKA activation independently of the classical cAMP pathway. Pharmacological blockade using FM101, a selective A₃AR antagonist, successfully suppressed fibrotic alterations in human proximal tubular epithelial cells. Furthermore, administration of FM101 in CKD mouse models markedly alleviated kidney dysfunction, inflammation, and interstitial fibrosis, corresponding with the suppression of the A₃AR-mediated non-canonical signaling pathways. Taken together, these findings suggest that A₃AR is a potential modulator of kidney fibrosis, and its pharmacological inhibition by FM101 offers a promising investigative strategy for CKD therapy.