Aminoglycoside-induced nephrotoxicity is one of the prevalent causes of acute kidney injury (AKI). Oxidative stress-mediated apoptosis of renal tubular cells is known to be a major mechanism of renal injury. Red ginseng extract (RGE) has been reported to possess antioxidant and immune-modulatory activities. We investigated the effect of RGE on gentamicin (GM)-induced apoptosis and oxidative stress in cultured renal tubular cells and animal model of GM-induced AKI. GM induced the generation of reactive oxygen species (ROS) with an increase in NADPH oxidase (NOX) activity and mitochondrial oxidation in NRK-52E cells that were ameliorated with RGE. GM-induced apoptosis of NRK-52E cells, which was associated with an increased expression of mitochondrial Bax, cytosolic cytochrome c, and cleaved caspase-9 and -3, along with a decrease in bcl-2 expression, was also blocked by RGE. In an animal model of GM-induced AKI, RGE treatment significantly attenuated renal dysfunction, cell apoptosis, and tubular damage. RGE ameliorated ROS production in rats with GM-induced AKI, as demonstrated by an increase in the reduced form of glutathione in renal cortex and a decrease in urinary excretion of 8-hydroxy-2'-deoxyguanosine. Our results suggest that RGE protects the kidney from GM-induced AKI via the mechanism of modulation of oxidative stress.