List of third-party and independent candidacies in United States Senate elections

This is a list of notable performances of third party and independent candidates in elections to the United States Senate.

It is rare for candidates, other than those of the six parties which have succeeded as major parties (Federalist Party, Democratic-Republican Party, National Republican Party, Democratic Party, Whig Party, Republican Party), to take large shares of the vote in elections.

In some of the listed cases a faction or factions of a state's major party ran against each other, often making it difficult to ascertain which was the mainline candidate and which was the bolter; in such cases, those candidates which are not listed on a standard major party line are still listed, but are not considered traditional third party victories as often these candidates sat in Congress as affiliated party members (barring cases like Joe Lieberman who, upon winning re-election in 2006 as a third-party candidate, sat as an Independent Democrat).

Listed below are Senate elections in which a third party or independent candidate won at least 5.0% of the vote. Winners are shown in bold and marked "elected" or "re-elected".

Indirect elections (before 1918)
Prior to the passage of the 17th Amendment, most states did not hold direct elections to the Senate, with senators instead being elected by the state legislatures. The results listed below are cases in which a third-party candidate won at least 5.0% of the legislative vote.