Department of the Taoiseach
|Formed||29 December 1937|
The Department of the Taoiseach (Irish: Roinn an Taoisigh) is the government department of the Taoiseach  of Ireland. It is based in Government Buildings, the headquarters of the Government of Ireland, on Merrion Street in Dublin.
The Department was created in 1937, simultaneous with the new Constitution replacing the Irish Free State's 1922 Constitution. The Department replaced the Department of the President of the Executive Council, just as the office of Taoiseach replaced the office of President of the Executive Council.
The civil servant who heads the Department of the Taoiseach is known as the Secretary General of the Department and also serves as the Cabinet Secretary.
- Taoiseach: Leo Varadkar, TD
- Secretary General of the Department: Martin Fraser, who is also the Secretary General to the Government and thus the country's most senior civil servant.
- Second Secretary General of the Department: Geraldine Byrne Nason, who has responsibility over the Office of the Tánaiste, the Economic Management Council and EU Affairs within the Department.
The main role of the Department is to support and advise the Taoiseach in carrying out various duties. The Department also supplies administrative support to the Government Chief Whip in respect of his duties and provides the Secretariat to the Government. The Department has a pivotal role in acting as a link between the President, the Taoiseach and other Departments of State.
In addition, the Department of the Taoiseach is involved in a number of other areas such as the development and co-ordination of policy in relation to economic and social development (Social Partnership), Northern Ireland, the European Union and Oireachtas reform. It also arranges State functions such as the annual National Day of Commemoration, Presidential inaugurations, State dinners and provides a protocol service to the Taoiseach of the day.
- Article 13.1.1° and Article 28.5.1° of the Constitution of Ireland. The latter provision reads: "The head of the Government, or Prime Minister, shall be called, and is in this Constitution referred to as, the Taoiseach." 
- Fitzgerald, Mary (13 July 2011). "Kenny appoints second secretary general". The Irish Times.