Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for atherosclerosis. Accumulated evidence has revealed that OSAS can induce systemic inflammation, oxidative stress, and endothelial dysfunction, which will contribute to the pathogenesis of atherosclerosis. T lymphocytes can be activated by inflammation and oxidative stress, resulting in the elevated cytotoxicity towards vascular endothelial cells. Thus, T lymphocytes play a key role in OSAS-related atherosclerosis development or progression via immuno-inflammatory alterations. This review described the current development of the role of T lymphocytes in OSAS-related atherosclerosis.