An important question for contemporary democracies is whether and the extent to which the high degree of ideological extremism, observed in many democracies, affects citizens’ electoral participation. While prior work has provided evidence of the link between ideological extremism and citizens’ electoral behavior, analysis of the Integrated Module of the Comparative Study of Electoral Systems (CSES) reveals large cross-national differences in that link. Specifically, in some countries, ideological extremism mobilizes citizens to vote in elections. In others, the opposite is found. And in a third group of countries, ideological extremism actually exerts no influence on citizens’ voting behavior. In this article, I perform the first analysis of these differences by studying the moderating role of party polarization. I hypothesize that the voting gap between ideological extremists and moderates will increase with party polarization as ideological extremists would have a party option that is more proximate to their ideological position and, consequently, they would perceive more utility from voting when party polarization is higher than when it is lower. Testing this prediction with the Integrated Module of the Comparative Study of Electoral Systems (CSES), I find evidence in support of it, result which stand up to several robustness checks. As such, this article provides important knowledge on the relation between ideological extremism and voter turnout.