Health professionals need a wide range of complex skills to perform their work efficiently. However, as in other sectors of the economy, there is not always a perfect match between the skills that health professionals have and the skills required in their jobs. Such skills mismatch raises concerns of a possible waste in human capital (when people are over-skilled for the work they do) or the quality and safety of health services (when they are lacking certain skills). This chapter introduces the concept of skills mismatch among health professionals, proposing a broad framework to analyse both the possibilities of over-skilling and under-skilling. It presents some evidence on the extent of skills mismatch in the health sector by using information reported by doctors and nurses in the 2011-12 OECD Programme for the International Assessment of Adult Competencies (PIAAC) and the 2010 European Working Conditions Survey (EWCS). The results from these two surveys indicate that there tends to be a greater level of skills mismatch among doctors and nurses than among other workers in technical or professional occupations. This chapter then goes on to review some policy levers that might be used to address issues of skills mismatch in the health sector, including policies to expand the scope of practice of certain providers to reduce any over-skilling, and policies related to continuous professional development to ensure that the skills of health care providers remain up-to-date and “fit to practice”.