With a focus on human behaviour and behaviour change, health psychology brings a powerful set of theories, evidence and practical tools to help to address real-world problems in health. Consultancy practice enables health psychologists to make a positive difference to health at scale. To do this, in addition to their scientific expertise, health psychologists also need to have the skills to engage with clients and stakeholders in what is effectively a ‘business’ context. Health psychology consultants need to understand the processes involved in consultancy in order to develop their knowledge, skills and confidence in consultancy practice. Stage models of consultancy do not fit well with the scientific-practitioner model or with the way consultancy is practised by health psychologists. This chapter presents a framework for consultancy in health psychology, building on the work of health psychology consultants, drawing on models from other types of consultancies and reflecting the extensive consultancy experience of the authors. The five overlapping processes in the framework are explained in a practical way so that health psychologists can recognise gaps in their consultancy expertise and ways of developing their skills.