Ethnic diversity has been shown to play a significant role in public goods provision, economic growth and government quality, to mention a few. However, we do not know which is the impact of ethnic diversity on turnout. In this article, we determine which dimensions of ethnic diversity affects turnout. To do so, we have gathered data from over 650 parliamentary elections in 102 democracies covering over a fifty-year period. Our models and seven complementary robustness checks show that elections in countries with more fractionalised, more polarised and more concentrated ethnic groups have a significantly and substantially lower turnout.