Hà Thúc Ký was a South Vietnamese opposition politician. During the presidency of Ngô Đình Diệm he was sentenced in absentia to 20 years in prison and arrested in October 1958, however, after the coup and assassination of Diệm in 1963, he was released by the rebel forces. He ran for president in the 1967 South Vietnamese presidential election, under the Đại Việt Revolutionary Party, a branch of the Nationalist Party of Greater Vietnam and was unsuccessful. In 1974, after President Nguyễn Văn Thiệu amended the "Regulations of the Political Party" into law, Ký filed an application at the Supreme Court to sue President Thiệu, declaring that the law was unconstitutional.