The literature on electoral participation has frequently focused on the turnout rates across countries. However, little effort has been devoted to explaining why some countries present higher variation across districts than others. In this paper I set out the relevance of this phenomenon and focus on explaining it cross-nationally. My central argument is that the nationalization of party systems is the main element driving this variation because of the impact of local party systems within a country. When the nationalization of the party system is low, differences in the number and/or the type of local parties change the voting incentives among districts, fostering differences in turnout rates within the country. I provide empirical evidence through two different samples of countries and nationalization indices accounting for the impact of ethno-linguistic fractionalization, district magnitude and variation in district competitiveness.