Marshall v. Holmes, 141 U.S. 589, is an 1891 decision of the United States Supreme Court on equitable relief, res judicata and fraud on the court in diversity jurisdiction. Justice John Marshall Harlan wrote for a unanimous Court that held it unconscionable to allow a state court's decision to stand that had been based on documents later exposed as forgeries. It permitted a federal case seeking to set that verdict aside to go forward.