William Strong (May 6, 1808 – August 19, 1895) was an American lawyer, jurist, and politician who served as an Associate Justice of the Supreme Court of the United States from 1870 to 1880 writing majority opinions in landmark cases like Strauder v. West Virginia.

William Strong attended the Monson Academy in Massachusetts, and graduated from Yale University in 1828, where he was a member of Brothers in Unity and Phi Beta Kappa.

Strong was elected to the Supreme Court of Pennsylvania in 1857 as a Democrat, succeeding James Armstrong, who had been temporarily appointed to the seat.

In December 1869, Justice Robert C. Grier announced his intention to retire from the United States Supreme Court effective February 1, 1870.

1873), Strong, riding on circuit, upheld an indictment under the Enforcement Act of 1870 when election officials prevented black Americans from voting.

Strong held that the Reconstruction Amendments allowed Congress to enact legislation punishing private individuals when a state failed to protect constitutional rights.

Strong served on the Supreme Court until December 14, 1880, when he retired despite still being in good health, partly to set an example for several infirm justices who refused to give up their seats.

After his retirement from the Supreme Court, Strong served as an arbitrator for an international dispute between Haiti and the United States, according to a 1884 agreement between the two nations.