It has become clear over the past few years that a variety of experimental autoimmune conditions are mediated by T cells bearing a highly restricted subset of antigen receptors. This restricted TcR usage raises important questions concerning not only the recognition of autoantigens, but also the pathogenic mechanisms underlying many models of autoimmunity. Furthermore, the extension of these findings in certain cases to human disease has raised the possibility of specific therapeutic immune intervention. In this review, we examine the available data on restricted T-cell receptor usage in autoimmune disorders and explore the interpretations and the theoretical and practical implications of these findings.