Within the recent UK policy agenda of Every Child Matters (Department for Education and Skills, 2004), multi-agency collaboration is becoming increasingly relevant to policy-makers and practitioners in the broad field of children's services. More generally, working together towards a common goal raises unique problematic issues for professionals from different backgrounds, over and above those issues arising from collaboration within a single profession or discipline. Such difficulties stem partially from the differing ideologies, working practices and priorities that are encountered when educational practitioners, social services practitioners and health practitioners aim to work collaboratively to further the interests of the children with whom they work. Recent research into multi-agency collaboration has mostly focussed on barriers to and facilitators of the process, and is often highly contextualised with relatively few attempts to generalise findings and develop theory.The current paper proposes a model of multi-agency collaboration, which has been developed by the author in response to the literature in the field, and incorporates aspects of theoretical developments in the field of team reasoning (eg Gilbert, 2005; Sugden, 2005).The model illustrates the factors influencing the success of multi-agency collaboration, and allows for variations in regulation and working practices in different aspects of children's services. This is the first time that the theory of team reasoning has been applied in such a context, and distinctions are made between current descriptions of multi-agency collaboration and the proposed model. The model describes the local context and details of the collaboration as being situated within the policy field. At the heart of the collaboration are personal contexts, with the individual as the unit of analysis, and collaborative processes, with the group as the unit of analysis. Team reasoning is suggested to be a key component of both the personal context and the collaborative process. The authors ask whether this role for team reasoning theory in the process of multi-agency collaboration is appropriate, and present the case for the use of team reasoning as a theoretical underpinning of the model. It is concluded that team reasoning is a valuable tool to use for consideration of multi-agency collaboration. The question is raised of how relevant the model is to a wide range of contexts, and it is suggested that the model is generalisable and able to take account of different management structures, and different types of collaboration, in and between a variety of sectors of children's services and beyond. Different ways in which the model will be tested and developed further are discussed. Potential uses for the model in its current and future states, in both educational policy and educational practice, are suggested.Department for Education and Skills (2004) Every Child Matters: Change for Children. Nottingham: DfES Publications. Gilbert, M. (2005) A theoretical framework for the understanding of teams. In N. Gold (Ed.) Teamwork: Multi-Disciplinary Perspectives. (pp. 22-32). Basingstoke: Palgrave Macmillan. Sugden, R. (2005) The logic of team reasoning. In N. Gold (Ed.) Teamwork: Multi-Disciplinary Perspectives. (pp. 181-199). Basingstoke: Palgrave Macmillan. Aiming for National or European Journal