The Independent Irish Party (1852-1858) was an Irish political party founded in July 1852 by 40 Liberal Irish MPs who had been elected to the Parliament of the United Kingdom of Great Britain and Ireland. It is sometimes mentioned as the Irish Independent Opposition Party, and colloquially known as the Pope's Brass Band because of their stance on the Ecclesiastical Titles Act. Its MPs were also called the "Irish Brigade".

It had two central aims:

The repeal of the Ecclesistical Titles Act, which banned Roman Catholic Bishops from re-assuming pre-reformation ecclesiastical bishropic titles in the United Kingdom, as well as the prohibition of the wearing of clerical outfits.
The adoption and enforcement of the Three Fs, namely
fair rent;
fixity of tenure;
free sale. (These would all have aided Irish tenant farms, all of whom lacked them.)

The Independent Irish Party initially achieved the balance of power in the House of Commons. It brought down Lord Derby's Tory ministry and enabled the leader of the Peelites Lord Aberdeen and Whigs to form a coalition government. However two Irish MPs, John Sadleir and William Keogh then broke ranks by joining this ministry, an act for which they were never forgiven in Ireland, where they were remembered with contempt a century later.

Some but not all Irish Liberal candidates in the 1852 election had pledged themselves to form an independent party in Parliament. This was done in their election address or at two conferences in 1852, one held by the Tenants League and the other about Religious Equality. 48 Irish MPs were elected after making such a pledge. One was unseated after an election petition.

The group began to nominate its own candidates in by-elections between 1852 and 1857 and had some limited success, winning four seats.

The party was damaged by weak leaders and by the lack of support its received from the Roman Catholic Church. Charles Gavan Duffy left in despair and went to Australia. Frederick Lucas proved an ineffective leader, while his successor, George Henry Moore, its new leader, having got elected in his Mayo constituency through clerical help, was defeated by clerical opposition at the 1857 general election. The party split over an internal row over its oath, and faded into oblivion. Members of the group participated in the meeting of MPs in 1859, which agreed to support the Second Palmerston Government and which is often regarded as the formal foundation of the Liberal Party.