This thesis provides a contribution to knowledge by demonstrating that deliberative theories of democracy have failed to take sufficient account of social difference and by arguing for a more complex and relational understanding of social identity to be considered in democratic theory. I argue that deliberative theories of democracy should not consider deliberators only as socially embedded actors but should consider social groups and social identity as a ground for political participation. I show how some of the main deliberative theories to date have failed to commit to a sufficient understanding of social identity, before demonstrating how identity should be conceived for the purposes of deliberative models. I further argue that, in view of the importance of social identity in political participation, we should understand our civic and political spheres as porous, rather than as distinct. Identity is not something we can ignore in political life, and attempts to minimise its workings are more likely to result in problems, than promote greater political harmony. I will demonstrate throughout the course of this thesis that attempts to efface, minimise or overcome identity in deliberative theory leads to that theory being unable to recognise some of the important workings of social identity in democracy.