The 2020 Los Angeles County elections were held on November 3, 2020, in Los Angeles County, California, with nonpartisan blanket primary elections for certain offices being held on March 3. Three of the five seats of the Board of Supervisors were up for election, as well as one of the countywide elected officials, the District Attorney. In addition, elections were held for various community college districts and water districts, as well as the Superior Court.

Municipal elections in California are officially nonpartisan; candidates' party affiliations do not appear on the ballot.

Three of the five seats of the Los Angeles County Board of Supervisors were up for election to four-year terms. Incumbent supervisors Janice Hahn and Kathryn Barger handily won re-election in the primary. In the second district, incumbent Mark Ridley-Thomas was term-limited and could not seek a fourth term, opting instead to run for Los Angeles City Council. State senator Holly Mitchell and Los Angeles City Councilor Herb Wesson advanced to the general election, eliminating former L.A. city councilor Jan Perry and Carson mayor Albert Robles. Mitchell won the general election, resulting in a supervisor board consisting entirely of women for the first time in its history.

Incumbent district attorney Jackie Lacey ran for re-election to a third four-year term. Following the murder of George Floyd and the subsequent protests advocating for criminal justice reform, Lacey's "tough-on-crime" policies were criticized and contrasted with those of her opponents, former San Francisco District Attorney George Gascón and public defender Rachel Rossi. Gascón defeated Lacey in the general election by a 7-point margin. Lacey became the first district attorney to lose re-election since Gil Garcetti lost to Steve Cooley in 2000.

U.S. senators

U.S. representatives

Local officials

The Compton Community College District held elections for its board of trustees in two areas on November 3. Incumbent Sonia Lopez of Area 3 was re-elected unopposed.