The Chairman of the Provisional Government of Southern Ireland was a transitional post established in January 1922, lasting until the creation of the Irish Free State in December 1922.

The Anglo-Irish Treaty of December 1921 was passed by the Irish Republic's Dáil Éireann. The British government also required it to be passed by the House of Commons of Southern Ireland, and for a legal government to be established. Michael Collins became Chairman of the Provisional Government (i.e. prime minister). He also remained Minister for Finance of Arthur Griffith's republican administration. An example of the complexities involved can be seen even in the manner of his installation. In theory he was a Crown-appointed prime minister, installed under the Royal Prerogative. To be so installed, he had to formally meet the Lord Lieutenant of Ireland, Viscount Fitzalan of Derwent (the head of the British administration in Ireland). According to republican history, Collins met Fitzalan to accept the surrender of Dublin Castle, the seat of British government in Ireland. According to British constitutional theory, he met Fitzalan to 'kiss hands' (the formal name for the installation of a minister of the Crown), the fact of their meeting rather than the signing of any documents, duly installing him in office.

After Collins's and Griffith's deaths in August 1922, W.T. Cosgrave became both Chairman of the Provisional Government and President of Dáil Éireann, and the distinction between the two became increasingly confused and irrelevant up until the creation of the Irish Free State.

List of Chairmen of the Provisional Government

• Michael Collins (in office January 1922 - August 1922)
• W.T. Cosgrave (in office August 1922 - December 1922)
• Position replaced by President of the Executive Council of the Irish Free State December 1922