Thoracic aortic aneurysms and dissection (TAAD) is a critical, life-threatening cardiovascular condition characterized by immune-mediated inflammatory infiltration and structural degradation of the aorta wall, which are pivotal in its etiology. In recent years, the significance of T lymphocytes in TAAD has increasingly garnered scientific attention. TAAD is a multifaceted vascular disorder characterized by the involvement of many immune cells, with T lymphocytes playing a pivotal role, particularly in the modulation of inflammatory responses, immunological control, and tissue damage. A comprehensive understanding of the T lymphocyte activation process in TAAD is crucial for the advancement of novel preventative and therapy strategies. This article evaluates the recent research advancements on the function of T lymphocytes in TAAD, aiming to offer novel insights for the future prevention and treatment of TAAD.