Universal suffrage (also universal adult suffrage, general suffrage or common suffrage) consists of the extension of the right to vote to adult citizens (or subjects) as a whole, though it may also mean extending said right to minors (Demeny voting) and non-citizens. Although suffrage has two necessary components, the right to vote and opportunities to vote, the term universal suffrage is associated only with the right to vote and ignores the other aspect, the frequency that an incumbent government consults the electorate. Where universal suffrage exists, the right to vote is not restricted by race, sex, belief, sexual orientation, gender identity, wealth, or social status. Historically, universal suffrage often in fact refers to universal adult male suffrage.

The concept of universal suffrage originally referred to all male citizens having the right to vote, regardless of property requirements or other measures of wealth. The first system to explicitly claim to use universal suffrage was France which is generally recognized as the first national system to abolish all property requirements for voting. In theory France first used universal (male) suffrage in 1792 during the revolutionary period, although the turmoil of the period made this ineffective. France and Switzerland have used universal male suffrage continuously since 1848 (for resident male citizens), longer than any other countries. The German Empire had universal male suffrage from its beginning in 1871. New Zealand became the first nation in the world to achieve universal suffrage in 1893.