The apoptotic or necrotic death of renal tubule epithelial cells is the main pathogenesis of renal ischemia/reperfusion-induced acute kidney injury (AKI). Pyroptosis is a programmed cell death pathway that depends on the activation of the caspase cascade and interleukin (IL)-1 cytokine family members. However, the role of pyroptosis in AKI induced by ischemia/reperfusion remains unclear. In this study, we found that the levels of the pyroptosis-related proteins, including caspase-1, caspase-11, and IL-1β, were significantly increased after 6 h of renal ischemia/reperfusion injury (IRI) and peaked at 12 h following injury. Enhanced pyroptosis was accompanied by elevated renal structural and functional injury. Similarly, hypoxia/reoxygenation injury (HRI) also induced pyroptosis in renal tubule epithelial NRK-52E cells, which was characterized by increased pore formation and elevated lactate dehydrogenase (LDH) release. In addition, the obvious upregulation of endoplasmic reticulum (ER) stress biomarkers, glucose-regulated protein (GRP) 78, and C/EBP homologous protein (CHOP), preceded the incidence of pyroptosis in cells treated with IRI or HRI. Pre-treatment with a low dose of tunicamycin, an inducer of ER stress, relieved IRI-induced pyroptosis and renal tissue injury. Silencing of CHOP by siRNA interference significantly decreased HRI-induced pyroptosis of NRK-52E cells, as evidenced by reduced caspase-11 activity and IL-1β generation. Therefore, we conclude that pyroptosis of renal tubule epithelial cells is a key event during IRI and that CHOP-caspase-11 triggered by overactivated ER stress may be an essential pathway involved in pyroptosis.