James Manuel Costa ComM (born April 13, 1952) is an American politician serving as the U.S. representative for California's 21st congressional district since 2023. He previously represented the 20th congressional district from 2005 to 2013 and the 16th congressional district from 2013 to 2023. A member of the Democratic Party, his district includes most of Fresno.

Costa served in the California State Assembly from 1978 to 1994, and then in the California State Senate from 1994 until 2002. During his time in the Assembly, he served as Majority Caucus Chair. Costa chaired the Blue Dog Coalition in the U.S. House of Representatives during the 116th Congress and chaired the Subcommittee on Livestock and Foreign Agriculture during the 117th Congress.

Costa was born on April 13, 1952, in Fresno, California. His parents were Manuel and Lena Cardoso Costa. All of his four grandparents immigrated from the Azores, a Portuguese archipelago in the North Atlantic, in the early 20th century. Three of them were unable to read or write and initially found work as laborers on dairy farms before eventually establishing their own. His parents grew up speaking Portuguese and did not learn English until they started school. He grew up working on the family farm.

Costa attended San Joaquin Memorial High School, a private Catholic school in Fresno, where he graduated in 1970. He then enrolled at California State University, Fresno (commonly known as Fresno State), earning a Bachelor of Arts degree in political science in 1974. While in college, he was a member of Sigma Alpha Epsilon and interned in the office of U.S. Representative B. F. Sisk.

Following his graduation, Costa worked as an aide to U.S. Representative John Krebs, assisting in policy matters related to California's Central Valley. He later became chief of staff to California State Assemblyman and future U.S. Representative Rick Lehman.

In 1978, Costa was elected to a seat in the California State Assembly. At the time of his election to the Assembly, he was the youngest member of the state legislature at age 26. He represented part of Fresno County in the legislature for 24 years, serving in the state Assembly for 16 years (1978–1994) and in the state Senate for eight years (1994–2002). He was a sponsor of the Costa-Hawkins Rental Housing Act, a bill signed into law in 1995 that prohibits rent control on single-family homes, condominiums, and any rental unit constructed after February 1, 1995.

From 2000 to 2001, Costa served as the president of the National Conference of State Legislatures.

In 2004, Costa entered the Democratic primary for the 20th Congressional District, which was opened up by the retirement of Cal Dooley, its seven-term incumbent. Dooley endorsed his chief of staff, Lisa Quigley, as his successor, but most of the state's Democratic Party establishment, including Senator Dianne Feinstein, endorsed Costa, who won the bruising primary and faced Republican state senator Roy Ashburn in November.^{[citation needed]}