Abdirizak Haji Hussein was a Somali diplomat and politician. He was the Prime Minister of Somali Republic from 14 June 1964 to 15 July 1967. From 1975 to early 1980, he also served as the country's ambassador to the United Nations. A former Secretary General of the Somali Youth League, Hussein played a leading role in the nation's early civilian administration.

The Somali Republic was formed by the union of the Trust Territory of Somaliland and the State of Somaliland. A government was formed by Abdullahi Issa Mohamud and Muhammad Haji Ibrahim Egal and other members of the trusteeship and protectorate administrations, with Haji Bashir Ismail Yusuf as President of the Somali National Assembly and Aden Abdullah Osman Daar as President of the Somali Republic. On 22 July 1960, Daar appointed Abdirashid Ali Shermarke as Prime Minister. On 20 July 1961 and through a popular referendum, Somalia ratified a new constitution, which was first drafted in 1960. The new constitution was rejected by Somaliland.