The Twenty-third Amendment (Amendment XXIII) to the United States Constitution extends the right to participate in presidential elections to the District of Columbia. The amendment grants the district electors in the Electoral College as though it were a state, though the district can never have more electors than the least-populous state. The manner in which the electors are appointed is to be determined by Congress. The Twenty-third Amendment was proposed by the 86th Congress on June 16, 1960; it was ratified by the requisite number of states on March 29, 1961.

The Constitution provides that each state receives presidential electors equal to the combined number of seats it has in the Senate and the House of Representatives. As the District of Columbia is not a state, it was not entitled to any electors prior to the adoption of the Twenty-third Amendment. As early as 1888, some journalists and members of Congress favored a constitutional amendment to grant the district electoral votes, but such an amendment did not win widespread support until the rise of the civil rights movement in the 1950s. The amendment was not seen as a partisan measure, and ratification of the amendment was endorsed by President Dwight D. Eisenhower and both major party candidates in the 1960 presidential election. The ratification of the amendment made the district the only entity other than the states to have any representation in the Electoral College.

The first presidential election in which the District of Columbia participated was the election of 1964. Starting with that election the District of Columbia has consistently had three members of the Electoral College, this being the constitutionally implied minimum number it is entitled to; notwithstanding the constitutionally entrenched limitation on its number of electors, the District's population has never reached the threshold where it otherwise would have been entitled to more than three. Since the passage of the Twenty-third Amendment, all but one of the district's electoral votes have been cast for the Democratic Party's presidential candidates. The Twenty-third Amendment did not grant the district voting rights in Congress, nor did it give the district the right to participate in the process that allows the Constitution to be amended. An unsuccessful proposed constitutional amendment to do this was proposed by Congress in 1978, but it was not ratified by enough states for it to be adopted. Many citizens of the district favor statehood or further constitutional amendments to address these issues.