The School Health Research Network is a policy–practice–research partnership established in Wales in 2013. The network aims to: provide health and well-being data for national, regional and local stakeholders, including schools; co-produce school-based health improvement research for Wales; and build capacity for evidence-informed practice in the school health community. School-focused engagement activities include providing member schools with bespoke Student Health and Well-being Reports, hosting school health webinars, producing schoolfriendly research briefings and holding annual events for schools. The network's model for co-producing research with schools is described and its impacts on schools is explored. These include more efficient recruitment of schools to research projects, school involvement in intervention development, schools beginning to embed evidence-informed practice by using their Health and Well-being Reports and other network resources, and securing funding to evaluate innovative health and well-being practices identified by schools. Drawing on the transdisciplinary action research (TDAR) literature, the article reflects on how TDAR principles have underpinned the progress of the network. The concept of reciprocity in the co-production literature, and its relevance to engagement with schools, is also explored, along with the network's contribution to our understanding of how we can build sustainable co-production at large scale in order to generate nationallevel action and benefit.