The Wisconsin Supreme Court is the highest and final court of appeals in the state judicial system of the U.S. state of Wisconsin. In addition to hearing appeals of lower Wisconsin court decisions, the Wisconsin Supreme Court also has the option to take original jurisdiction of cases, and serves as a regulator and administrator of judicial conduct and the practice of law in Wisconsin.

Justices on the Wisconsin Supreme Court are elected. The two most recent elections (2023 and 2025) received national attention. They both broke records for the most expensive judicial elections in U.S. history.

The Wisconsin Supreme Court normally sits in its main hearing room in the East Wing of the Wisconsin State Capitol building in Madison, Wisconsin. Since 1993, the court has also traveled, once or twice a year, to another part of the state to hear several cases as part of its "Justice on Wheels" program. The purpose of this program is to give the people of Wisconsin a better opportunity to understand the operations of the state supreme court and the court system.

The court is composed of seven justices who are elected in statewide, non-partisan elections. Each justice is elected for a ten-year term. Importantly, only one justice may be elected in any year. This avoids the sudden shifts in jurisprudence commonly seen in other state supreme courts, where the court composition can be radically shifted if two or three justices are simultaneously targeted for an electoral challenge based on their views on controversial issues. In the event of a vacancy on the court, the governor has the power to appoint an individual to the vacancy, but that justice must then stand for election in the first year in which no other justice's term expires.

After passage of a state constitutional amendment on April 7, 2015, the chief justice of the court is elected for a term of 2 years by the vote of a majority of the justices then serving on the court, although the justice so elected may decline the appointment. Prior to that amendment, the justice with the longest continuous service on the court served as the chief justice.

While the court is officially nonpartisan, its members are generally regarded as having consistent ideological positions. Justices Crawford, Dallet, Karofsky, and Protasiewicz are frequently described as liberals, while Justices Ziegler, Hagedorn, and Bradley are described as conservatives. Liberal justices and candidates are endorsed and electorally supported by the Democratic Party and related organizations, and conservatives have an equivalent relationship with the Republican Party. Justice Hagedorn was considered the court's "swing justice" prior to Justice Protasiewicz's investiture; while his campaign was supported by Republican organizations and he previously served as chief legal counsel to Republican governor Scott Walker, he has sided with the so-called liberal justices in several noteworthy cases.

The members of the court choose their chief justice every two years by majority vote. This method of choosing the chief justice is a recent change, from a 2015 constitutional amendment. The change was controversial at the time, even leading to a federal lawsuit by the outgoing chief justice, Shirley Abrahamson, after the loss of her role to Patience Roggensack.

Prior to 2015, the chief justice was simply the longest continually-serving member of the court. This was the method for most of the court's history, since 1889. Prior to 1889, the court's chief justice was a separate seat on the court, elected by the public.