Ethnic identity development and expression is an area of strong academic interest and political debate. Recent research across a range of national settings has substantially enhanced our understanding of the factors that shape ethnic identity among immigrants and their children. For the UK, Understanding Society has substantially enhanced the potential for addressing issues of ethnic identity, given its large sample size and multiple measures. Locating them within the broader field of identity research, this paper brings together insights from recent research on ethnic identity in the UK. It synthesises findings on: the contextual (neighbourhood, friendship) influences on minority and majority ethnic identities; the ways in which national and ethnic identities co-vary; the individual characteristics associated with different patterns of identity expression; and the relationship between political and ethnic identification. The paper highlights the importance of examining majority ethnic identity alongside minority identities, as well as recognising that the factors associated with identity expression, and how it becomes salient, differ for minorities and majority. The paper concludes by highlighting the potential for further work in this area, exploiting the unique features of Understanding Society.