The Office of the Prime Minister of the United Republic of Tanzania dates back to the year 1961 when the first Prime Minister of Tanganyika, the Father of the Nation, Mwalimu J.K. Nyerere, was appointed. According to Government Notice Number 415 of 1st December 1961 the function of the office then was to advice the Governor-General on all matters relating to the Government of Tanganyika.

The Office of the Prime Minister was retained as the head of government business when Tanganyika became a republic on 9th December 1962 with the President as Head of State.

The Union of Tanganyika and Zanzibar on 26th April 1964 brought into existence the United Republic of Tanzania. One of the major changes brought about by the Union was the establishment of the Office of the Second Vice President, which also took over the functional roles of the Office of the Prime Minister. The Office of the Prime Minister was re-established in 1972 and since that time it has continued to exist. The 1977 Constitution of the United Republic of Tanzania gave the office its current legal status by establishing the post of the Prime Minister.
Between mid 1980s to date, the Prime Minister’s Office has undergone several changes, with various ministerial functions being added and removed from the Prime Minister’s responsibilities, according to the prerogatives of the President of the United Republic of Tanzania. The major constitutional changes of 1984 added the role of Vice Presidency to the Prime Minister. From November 1985 to October 1995, the office was known as Office of the Prime Minister and First Vice President.

With the constitutional amendments of 1992 that brought in multiparty democracy in the country, a separate office of the Vice President was established, hiving off that role from the Prime Minister.