Matthew Martin Rosendale Sr. (born July 7, 1960) is an American politician. A Republican, Rosendale represents Montana's 2nd congressional district in the United States House of Representatives. Rosendale served in the Montana House of Representatives from 2011 to 2013, and in the Montana Senate from 2013 to 2017. From 2015 to 2017, he served as Senate majority leader. Rosendale was elected Montana state auditor in 2016 and held that position from 2017 to 2020. Rosendale ran unsuccessfully for the U.S. House of Representatives in 2014 and for the U.S. Senate in 2018. He was elected to represent Montana's at-large congressional district in 2020. After Montana regained its second House seat in the 2020 census, Rosendale was elected to represent the new 2nd congressional district in 2022. On February 9, 2024, he announced his candidacy for 2024 United States Senate election in Montana, looking to challenge Jon Tester again. Less than a week later, on February 15, 2024, Rosendale ended his campaign after Donald Trump endorsed his opponent Tim Sheehy in the Republican primary. Rosendale chose to run for reelection to his House seat, but withdrew from that race as well in March 2024.