Power, a concept at the heart of the health policy process, is surprisingly rarely explicitly considered in the health policy implementation literature for low and middle income countries. In an attempt to support empirical research on power, this paper outlines some of the key insights on power from implementation theory. It then describes examples of power that might be seen in health policy implementation settings, such as hospitals, clinics and the local bureaucracies in which these are embedded, and concludes with suggestions for ways of investigating power and ensuring sound judgments are made about its existence and its influence over policy implementation.