Seanad Éireann was the upper house of the Oireachtas (parliament) of the Irish Free State from 1922 to 1936. It has also been known simply as the Senate, First Seanad, Free State Senate or Free State Seanad. The Seanad was established under the 1922 Constitution of the Irish Free State. A number of constitutional amendments were made to change the manner of its election and its powers. It was eventually abolished in 1936 when it attempted to obstruct constitutional reforms favoured by the government. It sat, like its modern successor, in Leinster House.

A senate is a deliberative assembly, often the upper house or chamber of a bicameral legislature. The name comes from the ancient Roman Senate, so-called as an assembly of the senior and therefore considered wiser and more experienced members of the society or ruling class. However the Roman Senate was not the ancestor or predecessor of modern parliamentarism in any sense, because the Roman senate was not a de jure legislative body.