Background: A key aim of educational research is for findings to inform practice, thereby bringing about improvements in teaching and learning. However, the relationship between research and practice is complex, and there is often no clear link between changes in practice and research findings. One of the challenges for research and practice is breaking down barriers and finding effective and sustainable ways to translate research findings into practical solutions in the classroom. Purpose: This discursive paper focuses on describing the nature of the partnership working involved when a design-based research (DBR) approach was employed to bring researchers and practitioners together. The researchers and practitioners worked in collaboration to design a professional development (PD) programme, in order to solve classroom problems and enhance practitioners' research engagement. Sources of evidence: This paper describes the author's experience of using DBR to co-design a PD programme that was responsive to a particular context and practitioners' needs. It illustrates and exemplifies the ways in which the researcher-practitioner collaboration itself sits at the heart of the design process and enabled solutions to be found. The paper also considers the epistemological positions of the practitioners and researchers in the different stages of DBR. The context for the description is a mixed-methods intervention study conducted in two colleges of teacher education, which documented the design and refinement of a PD programme to facilitate teachers' effective use of technology to teach mathematics. Discussion and conclusions: The examples presented and discussed here suggest how a DBR process is able to facilitate fruitful collaborations between researchers and practitioners and increase engagement in research. By working with practitioners to design interventions such as PD programmes, DBR can provide a practical approach for improving practice and deepening the relationship between educational research and classroom practice.