This paper compares and contrasts five theoretical approaches to the study of industrial relations. They are Dunlop's systems model, pluralism, Marxism, cor poratism, and theories of regulation. In examining these competing theories atten tion is directed to the notion of the public interest, the role of the state, and the level of analysis. The paper concludes that the concept of the public interest has no useful analytical role to play in a theory of industrial relations, that the state should be viewed as an independent variable, and that a disaggregated societal-based model should be employed. Finally, the role of any institution, or part of the system, needs to be viewed in terms of its interaction with the total system, or other institutions or parts of the system.