The Iowa caucuses are biennial electoral events for members of the Democratic and Republican parties in the U.S. state of Iowa. Unlike primary elections in most other U.S. states, where registered voters go to polling places to cast ballots, Iowans instead gather at local caucus meetings to discuss and vote on the candidates. During both the presidential and midterm election seasons, registered Iowan voters vote in a per-precinct caucus for the party of which they are registered as a member. The caucuses are also held to select delegates to county conventions and party committees, among other party activities.

The Iowa caucuses used to be noteworthy as the first major contest of the United States presidential primary season. Although caucus-goers have been unrepresentative of the nation's overall ethnic demographic, caucuses are still seen by some as a strong indicator of how a presidential candidate will do in later contests. This could be seen as a "self-fulfilling prophecy", however, where candidates successful in Iowa are also more likely to be successful politicians in general. Candidates who do poorly in the Iowa caucus are likely to drop out in the following days.

The 2020 Iowa Republican caucuses and the 2020 Iowa Democratic caucuses took place on February 3, 2020. The Democratic caucus proved controversial after difficulties and errors in the reporting of the final vote totals. Iowa Democratic Party Chair Troy Price resigned on February 12, 2020 over the chaos resulting from the caucus.

On February 4, 2023, the Democratic National Committee announced that the Iowa caucuses would no longer be the first in the nation for the Democratic presidential nomination process. Under new party rules, Iowa and South Carolina will swap places for the 2024 Democratic Party presidential primaries.