Hammer DeRoburt, MP, KBE (September 25, 1922 - July 15, 1992) was the founding president of Nauru and ruled the country for most of its first twenty years of independence.

A survivor of the wartime Japanese deportation of all Nauruans to Truk (1942-1946), he was elected to the Local Government Council of Nauru in the 1950s; then elected head chief (1955), he was the chief negotiator on phosphate royalties with the colonial power, Australia, which administered the island as a United Nations trust.

DeRoburt led the country to independence on January 31, 1968, and was president for most of the period until August 17, 1989. In December 1976 younger politicians gained a majority and installed Bernard Dowiyogo as president, but DeRoburt returned to power in May 1978. He was also out of office for two short periods in September and December 1986.

He was given an honorary knighthood by Queen Elizabeth II in 1982.

He died in Melbourne in 1992.