This chapter investigates the strategies of, and interactions between, mainstream and populist radical right (PRR) parties in the Netherlands in order to assess to what extent the success of Dutch PRR parties can be explained by the different ways in which mainstream parties in the Netherlands engage with their PRR niche contender. It focuses on how mainstream and PRR parties compete over immigration and integration. The chapter argues that in the post-Lijst Pim Fortuyn (LPF) era the issue of immigration has become a concern for all mainstream parties. Migration is undoubtedly a crucial issue for the PRR. The PRR has played an important role in politicising immigration and in transforming the way in which immigration has been addressed in the Netherlands since the early 2000s. This occurred through its impact on public discourse but also through its influence on the stances taken by the other political parties in the context of increased electoral volatility.