The oxidative damage to vascular endothelial cells induced by smoking represents a significant pathogenic factor in the development of atherosclerosis. In the present study, we isolated ginseng oligopeptide extract (GOE), which emerges as a promising candidate for protecting human aortic endothelial cells (HAECs) from nicotine-induced oxidative stress. The underlying mechanisms were also explored. The GOE effectively reversed the decline in cell viability and protected HAECs from nicotine-induced oxidative damage by inhibiting the overproduction of intracellular reactive oxygen species (ROS) while preserving superoxide dismutase (SOD) activity. We identified five ginseng oligopeptides (GOPs) as the primary components of GOE. Furthermore, we demonstrated that GOE significantly alleviated nicotine-induced mitochondrial dysfunction in HAECs while promoting the nitric oxide (NO) release and the expression of GTP cyclohydrolase 1 (GTPCH1). Although the precise mechanism through which GOE mitigates nicotine-induced oxidative stress in HAECs remains to be fully elucidated, our findings indicate that GOP-1-5 serve as bioactive constituents of GOE and play a significant synergistic role in reducing nicotine-induced apoptosis and oxidative damages in HAECs. This is achieved through modulation of cellular antioxidant systems via maintaining balance within the Keap1/Nrf2/HO-1 signaling pathway. These findings suggest that GOE may function as a potential therapeutic agent against cigarette smoking-induced atherosclerosis.