The Wisconsin Senate is the upper house of the Wisconsin State Legislature. Together with the Wisconsin State Assembly they constitute the legislative branch of the state of Wisconsin. The powers of the Wisconsin Senate are modeled after those of the U.S. Senate. The Wisconsin Senate is controlled by the Republican Party, as it has been for 20 of the past 22 years (only 2009-2010 are exceptions).

The Wisconsin Constitution ties the size of the State Senate to that of the Assembly, by limiting its size to no less than 1/4, nor more than 1/3, of the size of the Assembly. Currently, Wisconsin is divided into 33 Senate Districts (1/3 of the current Assembly membership of 99) apportioned throughout the state based on population as determined by the decennial census, for a total of 33 senators. A Senate district is formed by combining three Assembly districts. Similar to the U.S. Senate, in addition to its duty of reviewing and voting on all legislation passed through the legislature, the State Senate has the exclusive responsibility of confirming certain gubernatorial appointments, particularly cabinet secretaries and members of boards and commissions. Senators are elected for four-year terms, staggered so that approximately half of the Senate is up for election every two years. If a vacancy occurs in a Senate seat between elections, it may be filled only by a special election. The Senate chamber is in the south wing of the Wisconsin State Capitol, in Madison. In February 2024, the legislative maps of the Senate, along with the State Assembly, were redrawn following a court decision that found them to be unconstitutionally gerrymandered in favor of Republicans.^[2]

The salary of all legislators serving in the 2025 Wisconsin Legislature is $60,924, which is an increase of 6.12% from the previous biennium. The speaker of the assembly also receives an additional $25 monthly stipend.^[3] In addition to salaries, senators outside Madison, Wisconsin may receive a per diem up to $115 to cover living expenses while they are in Madison on state business. Members of the Dane County delegation may receive a per diem of half the amount to cover expenses.

• C. Latham Sholes (1848–1850; 1856–1858), invented the QWERTY keyboard
• Angus Cameron (1863–1864; 1871–1872), former U.S. Senator from Wisconsin (1875–1885)
• Gaylord Nelson (1949–1958), former Governor of Wisconsin (1959–1963) and U.S. Senator from Wisconsin (1963–1981)
• Henry Maier (1951–1960), former Mayor of Milwaukee (1960–1988)
• James B. Brennan (1959–1962), former U.S. Attorney for the Eastern District of Wisconsin (1962–1969) and Milwaukee City Attorney (1972–1984)
• William Bablitch (1972–1983), former Justice of the Wisconsin Supreme Court (1983–2003)
• Tom Petri (1973–1979), former U.S. House Representative (1979–2015)
• Jim Sensenbrenner (1975–1979), former U.S. House Representative (1979–2021)
• Russ Feingold (1983–1993), former U.S. Senator from Wisconsin (1993–2011)
• John Norquist (1983–1988), former Mayor of Milwaukee (1988–2004)
• Tom Barrett (1989–1993), former U.S. House Representative (1993–2003) and former Mayor of Milwaukee (2004–2021)
• Gwen Moore (1993–2005), current U.S. House Representative (2005–present)
• Glenn Grothman (2005–2015), current U.S. House Representative (2015–present)
• Tom Tiffany (2012–2020), current U.S. House Representative (2020–present)
• Fred Risser (1962-2021), longest-serving state legislator in American history
• Scott Fitzgerald (1995–2021), current U.S. House Representative (2021–present)

• Wisconsin Legislature
• Wisconsin State Assembly
• Impeachment in Wisconsin

• Wisconsin State Senate Archived April 18, 2012, at the Wayback Machine official government website
• State Senate of Wisconsin at Project Vote Smart
• Wisconsin State Senate at Ballotpedia
• Legislature Salary

43°04′27.5″N 89°23′03.0″W / 43.074306°N 89.384167°W / 43.074306; -89.384167