Agrarian-based populism has an almost uninterrupted presence in Finnish politics. Its various manifestations are analysed in this chapter. The main focus is on party-based agrarian populism: the Finnish Rural Party (1959-1995) and its successor party, the True Finns (from 1995 onwards). The endurance of populism in Finland, apart from its organisation, is due to both continuity in relation to its main appeal – its anti-establishment position, the rhetorical construction of a united and threatened ‘people’, and the restoration of popular sovereignty – and transformations to the contextual references of these core populist ideas. The party that started as an agrarian populist party for rural smallholders is today a populist radical right-wing party, with nationalism, expressed in anti-immigration and anti-EU positions, becoming more salient and more radical for the True Finns. It is concluded that a process of radicalisation took place, which was key to their electoral breakthrough in 2011.