2018 Wisconsin Senate election

The 2018 Wisconsin Senate elections were held on Tuesday, November 6, 2018, at the Fall general election in Wisconsin. Seventeen of the 33 seats in the Wisconsin Senate were up for election&mdash;the odd-numbered districts. Before the election, Republicans held 18 seats and Democrats held 15 seats. Of the seats up for election, 10 were held by Republicans and 7 were held by Democrats. The primary election was held on August 14, 2018.

Republicans maintained control of the Senate, flipping one Democratic-held seat to enter the 104th Wisconsin Legislature with 19 of 33 Senate seats.

Results summary
Statewide results of the 2018 Wisconsin State Senate election:

Close races
Seats where the margin of victory was under 10%:
 * 1) State Senate district 25, 2.14%
 * 2) State Senate district 5, 2.4%
 * 3) State Senate district 31, 5.66%
 * 4) State Senate district 19, 6.5%
 * 5) State Senate district 17, 8.24%
 * 6) State Senate district 1, 9.08% (gain)

Special elections
Two special elections were held during 2018 for vacancies in the state Senate. Democrats won both special elections, for a net gain of two seats.

Retiring

 * Terry Moulton (R–Chippewa Falls), representing District 23 since 2010, did not run for re-election.

Seeking other office

 * Kathleen Vinehout (D–Alma), representing District 31 since 2006, ran for governor of Wisconsin, but lost in the primary.
 * Leah Vukmir (R–Brookfield), representing District 5 since 2010, ran for United States Senate but lost the general election.

Candidates and results
Results of the 2018 Wisconsin State Senate election by district: