This chapter underscores the merit of studying the emergence and growth of the radical right from a cleavage perspective, which sees party system change as rooted in large-scale transformations of social structure. The chapter begins by discussing explanations for the rise of the radical right in terms of the educational revolution, the processes of economic and cultural modernization, and globalization, showing where these perspectives converge and where they differ. It then goes on to show how the structuralist perspective has been combined with a focus on agency. Under conditions of multidimensional party competition, the behavior of mainstream parties is crucial, because it determines the relative salience of competitive dimensions and whether they offer space for radical right-wing challengers. Some of the most exciting recent research studies how the processes of dealignment and realignment structure the propensity of specific social groups such as the manual working class to support the radical right.