Radical right parties are becoming increasingly likely candidates to participate in government coalitions in Western Europe. Comparative research on the electoral performance of these parties in government is still scarce. Our overview of the electoral effects of government participation of six parties in national governments shows that they do not run a higher risk of losing votes after government participation than other parties. There is considerable variation, however. Some radical right parties experienced great losses, while others won additional support. Focusing on the ways in which radical right parties conducted themselves in government, we explore why some parties won votes and others lost in post-incumbency elections. We compare their policy achievements with regard to immigration and integration policies, the performance of their ministers, and the party coherence of the six parties in office. Our analysis shows that policy records do not fully explain the variation in post-incumbency electoral results. Weak performance and internal party conflict prevent parties from credibly laying claim to the policy achievements of coalition governments and demonstrate that some of these parties were not ready for office.