Atherosclerosis is a chronic inflammatory disease of the arterial wall where both innate and adaptive immune responses contribute to disease initiation and progression. Initial studies have focused on the role of T helper-1 (Th1) and Th2 responses in atherosclerosis, and more recently evidence has been published supporting a protective role of regulatory T cells in this disease. A third member of the T helper set, IL-17-producing T cells, now called Th17 cells, was recently described as a distinct lineage that play important role in autoimmune diseases. Here, we review the current knowledge on the role of effector and regulatory T cell responses in atherosclerosis and discuss the contribution of the Th17 to this disease.