The 2018 Washington State Senate elections took place as part of the biennial United States elections. Washington state voters elected state senators in 25 of the state's 49 Senate districts. The other 24 state senators were not up for re-election until the next biennial election in 2020. State senators serve four-year terms in the Washington State Senate. A statewide map of Washington's state legislative districts is provided by the Washington State Legislature here, Archived 2018-10-24 at the Wayback Machine.