Within sociology, the most important critical tradition in the study of employment relations is labour process theory. This body of theory and research has its roots in Karl Marx’s analysis of the capitalist labour process, but only came to prominence with Harry Braverman’s work in the 1970s. Labour process theory has developed over time, and drawn upon a variety of theoretical traditions, but nonetheless there are core themes that unite this approach. Most importantly, there is a recognition that because the labour process involves the attempt by employers to control production in pursuit of profit, the employment relationship is necessarily one characterised by conflict. Arising from this, labour process theory understands employment relations as being concerned with how managers and employees struggle over the control of production and the allocation of resources within a relationship characterised by what Paul Edwards has called ‘structured antagonism’. This chapter explores the development of labour process theory over time and its enduring legacy as a framework that highlights issues of workplace power, control and conflict, located within broader social and political structures.