Objective To explore the role of ATP-binding cassette sub-family G member 1 (ABCG1) in oxidative stress production induced by tumor necrosis factor α (TNF-α) and its possible mechanisms. Methods Human umbilical vein endothelial cells (HUVECs) were transfected with specific ABCG1 siRNA or ABCG1 overexpression plasmid or pretreated with liver X receptor agonist T0901317, then were cultured with TNF-α for 12 hours. Intracellular reactive oxygen species (ROS) levels were measured using 6-carboxy-2, 7-dichlorodihydrofluorescein diacetate, diacetoxymethyl ester (CDCFHDA-AM) fluorescence and nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) activity was measured by spectrophotometer. Real time PCR and Western blot were employed to measure the expression of Nox4, one of NADPH oxidase subunit and the expression of superoxide dismutase (SOD). Results ABCG1 upregulation inhibited TNF-α-induced oxidative stress. Furthermore, the activity of NADPH oxidase and the expression of Nox4 were also suppressed by ABCG1 overexpression, but the expression of antioxidant SOD was promoted. Conversely, downregulation of ABCG1 by ABCG1 siRNA both increased the ROS production and promoted the NADPH oxidase activity and Nox4 expression. However, the expression of SOD1 was inhibited. Conclusions The results suggest that ABCG1 attenuates TNF-α-induced oxidative stress by regulating NADPH oxidase and SOD.