The 2018 United States House of Representatives elections in Washington were held on November 6, 2018, to elect the 10 U.S. representatives from the state of Washington, one from each of the state's 10 congressional districts. The elections coincided with other elections to the House of Representatives, elections to the United States Senate and various state and local elections. All nine incumbents seeking re-election were re-elected, however the Democratic Party won the open-seat in the 8th District previously held by a Republican, improving from a 6-4 margin to a 7-3 margin.
