Katherine Moore Porter (born January 3, 1974) is an American politician and lawyer who has been the U.S. representative from California's 47th congressional district since 2023, previously representing the 45th congressional district from 2019 to 2023. She was elected as part of a Democratic wave in Orange County flipping the 45th district, covering much of south-central Orange County, including Irvine, Tustin, and Lake Forest along with large portions of Anaheim and Laguna Niguel. In 2022, she was reelected in the 47th congressional district following redistricting. In 2023, Porter announced her candidacy for the U.S. Senate, foregoing reelection to the House of Representatives. She was defeated after failing to advance from the nonpartisan primary won by Adam Schiff and Steve Garvey. Porter graduated from Yale University and Harvard Law School and has taught law at several universities, including the University of California, Irvine, the William S. Boyd School of Law, and the University of Iowa. In the House, she was deputy chair of the Congressional Progressive Caucus and has received media attention for her questioning during congressional hearings.