Seventeen seats in the Wisconsin Senate are up for election on Nov. 3. Heading into the election, Republicans have an 18-15 majority. Democrats need to win at least two Republican districts, while maintaining their own, to gain a majority in the Senate. Republicans can lose no more than one district to maintain their majority. Republicans have held a majority since 2011.

Wisconsin Senate elections are staggered and only half the chamber is up for election every two years. This means this is the first time this set of seats is up for election since Wisconsin redrew its legislative maps in 2024. The Wisconsin Supreme Court ordered the state to draw new maps in a 4-3 decision on Dec. 22, 2023. In the 2024 elections, Democrats gained four seats in the state Senate and 10 seats in the state House.

Wisconsin has a divided government, with Republicans holding majorities in both legislative chambers and Tony Evers (D) serving as governor. If Democrats win a majority in the Assembly and the Senate, and maintain the governorship, they will gain a Democratic trifecta. If Republicans maintain majorities in both legislative chambers and win the governorship, they will gain a Republican trifecta. If neither party wins control of the legislature and governorship, Wisconsin will remain divided.

The Democratic Legislative Campaign Committee (DLCC) has targeted five Senate districts, including one that Democrats already hold. The Republican State Leadership Committee (RSLC) includes Wisconsin in its Top Defensive Battleground Chambers list and has targeted three Senate districts, all of which Republicans already hold.

Ballotpedia considers six Senate districts to be battlegrounds. These include districts that had a margin of victory within five percentage points in 2024, DLCC and RSLC targets, and districts with an election forecast rating of Toss-up, Lean D/R, or Tilt D/R. Democrats represent one battleground and Republicans represent five. Four districts are open, while the other two districts have an incumbent running. To read more about these districts, click here.

The Wisconsin Senate is one of 88 state legislative chambers with elections in 2026.