This chapter reviews the growing literature on compulsory voting’s consequences. Compulsory voting has an unsurprising upward impact on voter participation, which lessens the impact of many socioeconomic and demographic forerunners of turnout, thereby making the composition of the voting population better reflect the distribution of eligible voters. Further, invalid balloting tends to be more common under compulsory voting. Compelled voters are also less likely to cast ballots that correspond with their preferences. Many studies indicate that mandatory voting has an educative effect and can socialize people into political engagement, with others casting strong doubt on this possibility. A small number of studies have assessed whether compulsory voting shapes attitudes, election outcomes, the behavior of political parties, policy characteristics, and income growth and inequality, with few clear patterns yet established. Compulsory voting laws have the greatest impact where sanctions for abstention are enforced and meaningful.