Thyroid-associated ophthalmopathy (TAO) is considered to be an autoimmune inflammatory disorder of the extraocular muscles and the orbital fat/connective tissue. Recent studies analyzing T cells infiltrating retrobulbar tissues generated important insights into the immunopathogenesis of TAO. The present review focuses on advances in our understanding of mechanisms responsible for the autoimmune inflammation in TAO, especially T cell migration to the inflammatory site, T cell activation by autoantigens and costimulatory signals and their cytokine profile. The elucidation of these processes might lead to the development of novel therapeutic strategies directed against autoreactive T cells.