This chapter examines the evolution of cultural diversity, a concept of multiculturalism, as an ideology. Aside from cultural diversity, multiculturalism has three other inter-related concepts or values: identity, community, and citizenship and equality. The chapter first considers the link between migration and cultural diversity before discussing the routes to cultural diversity within modern states, especially immigration into European societies in the period since the Second World War. It then explores the relationship between the national and global dimensions of cultural diversity as well as the attitudes of other ideological perspectives, such as liberalism, socialism, conservatism, nationalism, and feminism, to cultural diversity. It also asks whether multiculturalism is an ideology in its own right and how multiculturalist ideology has been expressed in political movements and shaped government policies. Finally, it assesses the nature of, and reasons for, the recent backlash against multiculturalism in European societies.