Brian Jeffrey Mast (born July 10, 1980) is an American politician and U.S. military veteran who has served as the U.S. representative for Florida's 21st congressional district since 2017. The district, numbered as the 18th district before the 2020 redistricting cycle, includes portions of the Palm Beaches and Treasure Coast. Mast is a member of the Republican Party. A veteran of Operation Enduring Freedom, Mast lost both his legs while serving as a U.S. Army explosive ordnance disposal technician in Afghanistan in 2010.