Voter turnout has been in a trend of gradual decline in most established democracies in recent decades and the reasons for this are by no means fully understood. While most studies agree that the trend is largely driven by younger generations voting less than older cohorts, the individual-level mechanisms of their declining propensity to vote are still disputed. A major distinction in the literature on democratic developments is that between theories of political apathy and political alienation: whether citizens are less interested in politics or still interested but instead estranged from their political systems. An interesting test for these different explanations can be found in Scandinavia: While Norway and Sweden have intimate historical, political and cultural similarities, Norway has been experiencing gradual turnout decline, while there has been no clear overall trend in Sweden. This study uses a combined dataset of over 50.000 respondents from 31 national election studies in these two countries from 1956-2013 to test the relative roles of apathy, alienation and generational dynamics in explaining these different trends in turnout. The results indicate that apathy has been declining while alienation has been rising in both countries. However, in Norway, those who are more apathetic today are much less likely to vote than apathetic citizens were in the past. The youngest generations are also significantly more apathetic and less likely to vote in Norway than in Sweden. These dynamics appear to account for the larger trend of turnout decline in Norway.