Under New Labour, partnerships have emerged to become a central mechanism of service delivery in social policy. In response to this development, a number of papers and texts have appeared that have questioned the claims made for the benefits of partnerships by politicians and policy makers. In particular, the gap between the rhetoric of inclusiveness and the practice of exclusion in partnership working has been highlighted. However, as pertinent as these insights are, it is argued here that extant research into partnerships in social policy remains theoretically undeveloped, characterised by one-sided approaches that either lack critical edge or are dismissive of the potential of partnership working. What is required is an approach that addresses the deeper contradictions of partnerships in social policy and the structuring relations of power underpinning the conceptions of partnerships. Drawing on key concepts in social and political theory, this article proposes a theoretical framework that focuses on the dynamic and contextual nature of partnership. In short, a differentiated theory of partnership is offered as a means of facilitating a more realistic understanding of the limits and possibilities of partnership working. A case study on partnerships in sport policy is used to illustrate the analysis.