This chapter will be considering how sociology can contribute to both the theory and the practice of health promotion. It is my contention that many sociological categories are implicit in the work of health promotion and that articulating them can only improve our knowledge and how we use it. The chapter falls into four main sectors. The first, ‘What is sociology?’, offers a short introduction to the main theoretical approaches of the discipline and to its key concepts. Clearly, space here is limited and I would recommend any interested students to refer to more comprehensive introductory texts. The second section, ‘Sociology of health and illness’, briefly considers the role of the discipline in the field of health and illness. This charts its development from being in the service of medicine, to analysing the professional organization of medicine, to incorporating the perspectives of ‘ordinary’ people, to its present position of providing a critique of medical knowledge and practice.