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.

Women's suffrage is the right of women to vote in elections. At the beginning of the 18th century, some people sought to change voting laws to allow women to vote. Liberal political parties would go on to grant women the right to vote, increasing the number of those parties' potential constituencies. National and international organizations formed to coordinate efforts towards women voting, especially the International Woman Suffrage Alliance.