Hypoxia, one of the most common causes of kidney injury, is a key pathological condition in various kidney diseases. Renal fibrosis is the terminal pathway involved in the continuous progression of chronic kidney disease (CKD), characterized by glomerulosclerosis and tubulointerstitial fibrosis (TIF). Recent studies have shown that hypoxia is a key factor promoting the progression of TIF. Loss of microvasculature, reduced oxygen dispersion, and metabolic abnormality of cells in the kidney are the main causes of the hypoxic state. Hypoxia can, in turn, profoundly affect the tubular epithelial cells, endothelial cells, pericytes, fibroblasts, inflammatory cells, and progenitor cells. In this chapter, we reviewed the critical roles of hypoxia in the pathophysiology of TIF and discussed the potential of anti-hypoxia as its promising therapeutic target.