When we consider the literature that has been produced exploring approaches to public health ethics, it is rare to find any mention of solidarity. One obvious conclusion is that solidarity is a meaningless or superfluous consideration. We suggest that this is not the right conclusion to draw, and that we must first understand what solidarity is and then consider what difference it might make to thinking about issues in public health ethics. In this paper we, first, outline some of the existing approaches to public health ethics and suggest that they often involve a set of questionable assumptions about the nature of social relations as well as a clear commitment to particular values. A failure of imagination in relation to solidarity is not, however, an argument against taking the concept seriously. Second, we propose a particular account of solidarity, suggest reasons why it is important for thinking about ethical issues in public health, and suggest how it relates to other relevant values. We argue that it is essential to engage with the issue of where we ought to place solidarity within our debates and frameworks for public health ethics.