Conventionally citizenship has been understood as membership in nation states requiring certain rights and providing certain entitlements. Over the last twenty years, critical perspectives asserted that citizenship is not merely membership, let alone membership of a state. It is now argued that historically and theoretically citizenship involves a distinction between an outside and inside and often its boundaries become the sites of social struggle. Critical perspectives on citizenship invite us to think of citizenship as processes by which political subjectivity, understood as the right to make claims to rights, can be recognised and enacted. As these perspectives allow us to think critically about citizenship beyond membership and the nation state, in this thesis I focus first on the mechanism related to the logic of citizenship that dismisses political agency of those who do not count as political subjects and makes them into what I refer to as ‘citizen outsiders’. Second, I draw on critical perspectives on citizenship and ethnographic methods to examine how Romanian Roma in an East London borough, who are discursively constituted as lacking capacities to act as citizens, contest the ways they are problematised. By focusing on their everyday life struggles as acts of citizenship, I argue that Roma in London do make claims to rights and, in doing so, enact themselves as citizens. Finally I draw conclusions about the ways Roma are problematised and how Roma disrupt these positioning with various acts of citizenship.