This paper draws upon a number of recently-completed NFER projects on how UK schools have been working together to foster the development of innovative ideas and to share good practice for their mutual benefit. There is an assessment of 'what works?' in school partnerships and networks and what the main challenges are for this type of educational working. The pros and cons of different models of partnerships, including views on the role of Local Education Authorities (LEAs), are also considered.Many of the partnerships studied were developed in the context of UK policies and initiatives designed to raise standards of achievement in schools. These included Excellence in Cities, the Specialist Schools programme, the Beacon Schools initiative, Education Action Zones and Networked Learning Communities. The findings presented in the paper are not only situated in this strategic context, but are also expressed in terms of school partnership working in general. Consequently, they should be of interest to researchers and educationists from any countries where the school system involves partnerships or learning communities, or where there are plans for such forms of working.The paper is informed by the outcomes of a literature review on the topic of school partnership working (including Networked Learning Communities, which are a comparatively recent development). There are also detailed empirical findings based on fieldwork carried out in 12 case-study Local Education Authority (LEA) areas. In each of these areas the research team interviewed the key education officers or advisers who were responsible for overseeing school partnership working (or the partnership-based policies identified above). In addition, a number of schools were visited and the headteachers, selected teachers and students were asked about the benefits and challenges of school partnership working. To date, this has been an under- researched area of educational policy: the paper highlights and elaborates upon some important messages about the ways in which school partnerships and networks should be planned and implemented. Respondents suggested, for example, that there should be more strategic thinking about partnership working. What are these partnerships for and how exactly will they contribute to the sharing of best practice and improved teaching and learning? How can purposeful, meaningful, 'natural' partnerships be developed? Also, what forms should the partnerships take? Egalitarian relations, or partnerships based on mutual interest and respect, appear to be more successful than 'expert-client' type partnerships. School networks and partnerships may well be a central way forward for educational policies in European countries, but a great deal of thought is required if these are to be implemented successfully, with maximum benefit for those who teach and learn in the institutions involved.