The Irish Parliamentary Party was formed in 1874 by Isaac Butt, the leader of the Nationalist Party, replacing the Home Rule League, as official parliamentary party for Irish nationalist Members of Parliament (MPs) elected to the House of Commons at Westminster within the United Kingdom of Great Britain and Ireland up until 1918. Its central objectives were legislative independence for Ireland and land reform. Its constitutional movement was instrumental in laying the groundwork for Irish self-government through three Irish Home Rule bills.

Isaac Butt was an Irish barrister, editor, politician, Member of Parliament in the House of Commons of the United Kingdom, economist and the founder and first leader of a number of Irish nationalist parties and organisations. He was a leader in the Irish Metropolitan Conservative Society in 1836, the Home Government Association in 1870, and the Home Rule League in 1873. Colin W. Reid argues that Home Rule was the mechanism Butt proposed to bind Ireland to Great Britain. It would end the ambiguities of the Act of Union of 1800. He portrayed a federalised United Kingdom, which would have weakened Irish exceptionalism within a broader British context. Butt was representative of a constructive national unionism. As an economist, he made significant contributions regarding the potential resource mobilisation and distribution aspects of protection, and analysed deficiencies in the Irish economy such as sparse employment, low productivity, and misallocation of land. He dissented from the established Ricardian theories and favoured some welfare state concepts. As editor he made the Dublin University Magazine a leading Irish journal of politics and literature.