This paper discusses the contribution that practice-research networks can make to support critical professional development in the Learning and Skills sector in England. By practice-research networks we mean groups or networks which maintain a connection between research and professional practice. These networks stem from the philosophy of practitioner and action research in education. We use two examples both from higher and further education in England where continuing professional development has become a mandatory requirement for teachers in the Further Education (FE) sector. Our examples suggest that critical professional development can occur and although we are able to begin to identify some of the ways that these networks operate it is less clear which appropriate theories should support our work. The second part of the paper therefore explores some theoretical perspectives that focus on networks operating as systems. We discuss Actor Network Theory and Activity Theory which show how networks are populated by individuals with agency and suggest that a helpful way to contextualise the benefits of networks is provided by the concept of expansive learning providing a different understanding of how professional learning and development take place.