T cells are critical players in adaptive immunity, driving the tissue injury and organ damage of patients with autoimmune diseases. Consequently, investigations on T cell activation, differentiation, and function are valuable in uncovering the disease pathogenesis, thus exploring promising therapeutics for autoimmune diseases. In recent decades, accumulating studies have pinpointed immunometabolism as the fundamental determinant in controlling T cell fate. Specifically, mitochondria, as a hub of intracellular metabolism, connect glucose, lipid, and amino acid metabolic pathways. Herein, we summarize metabolic adaptations of mitochondrial oxidative phosphorylation and the relevant glucose, lipid, and amino acid metabolism during T cell activation, differentiation, and function. Further, we focused on current updates of the molecular bases for metabolic reprogramming in autoimmune T cells and advances in exploring metabolic-targeted therapeutics against autoimmune diseases. This might facilitate the in-depth understanding of autoimmune pathogeneses and the clinical management of autoimmune diseases.