The number of think tanks operating in the UK is increasing, providing an ever important source of ideas and research for policy audiences. They have been framed by some as useful intermediaries between research and policy, which academics aiming to influence policy might seek to emulate. Yet, there has been very little empirical work to explore how think tanks employ research, or on whose behalf they operate. This paper draws on two qualitative research projects to begin addressing this gap by exploring the role of British think tanks in debates about two major public health concerns: tobacco control and health inequalities.