Who was the first female justice on the U.S. Supreme Court?

Sandra Day O'Connor was the first female justice on the U.S. Supreme Court.

President Ronald Reagan nominated O'Connor in 1981 to replace retiring Justice Potter Stewart. The Senate confirmed her unanimously, 99–0, and she took her seat on September 25, 1981. Her appointment fulfilled Reagan's campaign promise to place the first woman on the Court.

O'Connor had already broken barriers in Arizona. She served in the Arizona Senate, became the state's first female majority leader, and was later appointed to the Arizona Court of Appeals. On the Supreme Court, she often occupied a pivotal position in closely divided cases and became one of the most influential justices of her era.

A common mix-up is Ruth Bader Ginsburg, who was the second woman on the Court, joining in 1993. Sonia Sotomayor became the third woman and the first Latina justice in 2009, while Elena Kagan became the fourth woman in 2010. O'Connor retired in 2006 and died in 2023.