Janet Claire Protasiewicz is an American attorney and jurist from Wisconsin who has served as a justice of the Wisconsin Supreme Court since August 2023. Protasiewicz was elected to the court in the 2023 election, after previously serving as a Milwaukee County circuit court judge in from 2014 to 2023 and as an assistant district attorney in Milwaukee for 26 years.

The Wisconsin Supreme Court is the highest appellate court in Wisconsin. The Supreme Court has jurisdiction over original actions, appeals from lower courts, and regulation or administration of the practice of law in Wisconsin.