Cardiovascular diseases (CVDs), largely due to atherosclerosis, are the major causes of death in today's world. Atherosclerosis is a chronic inflammatory condition initiated by retention and accumulation of cholesterol-containing lipoproteins, in particular low-density lipoprotein (LDL), in the artery wall. This initiates pathological responses of immune cells that lead to atherosclerotic plaque formation. T cells are present during all stages of the disease, and play an essential role in the initiation and progression of plaques. Whereas most T effector cell responses have been suggested to aggravate atherosclerosis, regulatory T cells (Tregs) have been shown to limit inflammation and inhibit the formation of lesions. In addition to their effects on the local pathological process, T cells and their released mediators modulate systemic lipid metabolism and can increase risk of CVDs. Such knowledge on the pathological and protective function of these cells has led to significant advances in the field. This review examines experimental and pre-clinical studies approaching the manipulation of cellular immunity in atherosclerosis. Modulation of T cells responses by vaccination, antibody therapies, dendritic cell based-therapies, and using amino acid-derived metabolites have shown benefits against atherosclerotic plaque progression in animal models. The clinical benefit of T cell-based therapies in humans still requires further investigation.