The Squad is an informal progressive and left-wing faction of the Democratic Caucus in the U.S. House of Representatives. Members of the Squad are all members of the Congressional Progressive Caucus. The Squad comprises the furthest left faction of the Democratic Caucus.

The squad was initially composed of four members elected in the 2018 United States House of Representatives elections: Alexandria Ocasio-Cortez of New York, Ilhan Omar of Minnesota, Ayanna Pressley of Massachusetts, and Rashida Tlaib of Michigan. The grouping expanded to six following the 2020 United States House of Representatives elections, with newly elected Jamaal Bowman of New York and Cori Bush of Missouri joining. Following the 2022 elections, the squad grew to nine with the addition of Greg Casar of Texas, Summer Lee of Pennsylvania, and Delia Ramirez of Illinois. After the 2024 elections, the group reduced to seven, as Bowman and Bush were defeated in their primaries and left at the beginning of the 119th Congress.

The Squad's members have been supported by the Justice Democrats political action committee, and are on the left wing of the Democratic Party. Ocasio-Cortez, Pressley, Bush and Bowman were initially elected to Congress after unseating incumbents in primary challenges. All but Lee represent safe seats, with Cook Partisan Voting Index scores of at least D+20. Geographically, all but the Texan Casar hail from the Midwestern United States or Northeastern United States. All but Omar, Pressley, and Ramirez are currently or formerly affiliated with the Democratic Socialists of America.^{[citation needed]}

The Squad has been said to represent the advocacy of progressive policies that some in the younger political generation support, such as Medicare for All, the Green New Deal, and tuition-free college, which the party leadership may not support. Ocasio-Cortez coined the name "Squad" in an Instagram post a week after the 2018 election. The photo, taken at a VoteRunLead event where the four founding members spoke, subsequently went viral. The grouping has since officially adopted the moniker by launching the Squad Victory Fund, a political action committee.

The colloquial use of the word "squad" arose from East Coast hip hop culture and describes "a self-chosen group of people that hope you want to identify with them". Its use by Ocasio-Cortez signaled familiarity with millennial slang as a playful reference to youth social cliques. Hip-hop originated in her home borough, The Bronx. Musical acts with "Squad" in their names and lyrics have existed since the 1990s.

The New York Times considers the Squad sui generis, not fitting neatly into the usual congressional groups: the gang (a bipartisan group focused on particular legislation) or the caucus (a pressure group based on special interests). It notes that the term has a militaristic connotation, conveying values of self-defense, allegiance, and having "something important to protect". Some Republicans have used the moniker pejoratively, but the four original women use it to express solidarity among themselves and with supporters. For example, the Justice Democrats quoted Pressley saying: "We are more than four people... Our squad includes any person committed to creating a more equitable and just world." Before new members joined the original 2018 elected members, President Trump referred to the Squad as "AOC+3"

The average age of the Squad was 38.3 as of mid-2019, nearly 20 years under the overall House average age of 57.6.

Ocasio-Cortez and Pressley unseated Joe Crowley and Mike Capuano, respectively, in primary elections. Omar won the seat previously held by Democrat Keith Ellison, who retired from the House to successfully run for Attorney General of Minnesota, and Tlaib won the seat once held by Dean of the House John Conyers, who resigned in 2017 after nearly 53 years in Congress. At least three Squad members provided fundraising and volunteer assistance during the other members' campaigns.