Gilbert Owen Nations (1866–1950) was an American lawyer and judge from Washington, D.C. who campaigned against Roman Catholicism in the United States. In 1924, he was the presidential nominee of an organization called the American Party. He was also a professor of Roman and Papal law at American University in Washington, D.C. He began practicing law in Missouri in 1902. Nations served as a probate judge in St. Francois County, Missouri. He moved to Washington D.C. in 1916. He died in 1950 in Park Ridge, Illinois.