In this chapter the authors explore recent advances in Labour Regulation Theory. This exposition of modern theoretical developments follows a brief history of efforts to explain the processes by which the rules of work are determined and the substantive character of the rules themselves. The authors begin by tracing the evolution of bargaining structures theory, and discuss how our own contributed concepts of ‘complexity’ and ‘congruence’ help to address several shortcomings in the traditional theory. They also consider the way in which Labour Regulation Theory has been enriched through research on the influence of institutional and market forces on the shape of labour regulation as well as the contributions of the socio-legal theorists. The chapter, while pointing to the growing explanatory power of Labour Regulation Theory, also contemplates how it might be further enhanced in future.