Programmatic approaches to assessment provide purposeful and meaningful assessment yet few examples of their development exist. The aim of this study was to describe the development of a programme of assessment using a participatory action research (PAR) approach. Nine work-based assessors together with three academics met on six occasions to explore the current approach to competency-based assessment in the placement component of a dietetics university course, the findings of which were used to design a programme of assessment. Findings revealed disconnect between current assessment approaches and best practice. The PAR methodology fostered a shared vision for the design of a programmatic approach to assessment and strong leadership was essential. Participants experienced a philosophical shift in their views towards assessment, supporting the implementation of a new assessment programme. This paper is the first to describe a PAR approach as a feasible and effective way forward in the design of programmatic assessment. The approach engaged stakeholders to strengthen their abilities as work-based assessors and produced champions for best practice assessment.