Elections to the European Parliament take place every five years by universal adult suffrage; with more than 400 million people eligible to vote, they are the second largest democratic elections in the world after India's.

Universal suffrage or universal franchise ensures the right to vote for as many people bound by a government's laws as possible, as supported by the "one person, one vote" principle. For many, the term universal suffrage assumes the exclusion of the young and non-citizens. At the same time, some insist that more inclusion is needed before suffrage can be truly universal. Democratic theorists, especially those hoping to achieve more universal suffrage, support presumptive inclusion, where the legal system would protect the voting rights of all subjects unless the government can clearly prove that disenfranchisement is necessary. Universal full suffrage includes both the right to vote, also called active suffrage, and the right to be elected, also called passive suffrage.