This chapter analyses the factors informing and sustaining sectarian hostility, victimisation and segregation with a view to understanding the changing nature of this deeply embedded form of prejudice. It outlines the specific characteristics of sectarianism in Northern Ireland, from the establishment of the province and the ensuing ‘Troubles’ period, through to the legacy of this conflict in the form of paramilitary groups, identity symbolisers and ‘peace’ measures which serve to further segregate opposing communities. Deep-rooted cultural differences continue to demarcate and dictate interactions between the ‘two communities’ to a point whereby ‘sectarianism’ is almost synonymous with Northern Ireland. Northern Ireland has dominated much academic research and scholarship, yet is less than a century old. Northern Ireland’s population is at its most balanced: 48 per cent Protestant and 45 per cent Catholic. Significant legal, social and political changes have enabled a more peaceful Northern Ireland.