This chapter examines the Northern Ireland party system and the role that it has played in structuring the conflict. It explores the relationship between party support and religion since 1968, and the political engineering that the British government has experimented with in order to try and weaken the political salience of religion. The chapter includes the social and demographic changes that have taken place since the start of the Troubles and demonstrates their implications for party fortunes. It discusses the electoral institutions with a particular focus on the burden that they place on the parties. The chapter deals with the patterns of party competition, showing how intra-community party competition is now more important than inter-community party competition. It analyses the social bases of the parties. The chapter evaluates if any of these changes will lead to the development of a pluralist democracy.