The Treason (Ireland) Act 1854 (17 & 18 Vict. c. 26) is an Act of the Parliament of the United Kingdom of Great Britain and Ireland. It extended part of the Treason Act 1708 to Ireland, specifically the rules about giving the defendant advance notice of the witnesses and jurors in his case. It was repealed as regards Northern Ireland by the Treason Act 1945, which abolished the unique procedural rules which applied in treason cases. As of 16 January 2020^[update] it remains in force in the Republic of Ireland.^[2]

The rule in the 1708 Act which was extended to Ireland was as follows:

"...[W]hen any person is indicted for high treason or misprision of treason, a list of the witnesses that shall be produced on the trial, for proving the said indictment, and of the jury, mentioning the name, professions, and place of abode of the said witnesses and jurors, be also given at the same time that the copy of the indictment is delivered to the party indicted; and that copies of all indictments for the offences aforesaid, with such lists, shall be delivered to the party indicted, ten days before the trial, and in presence of two or more credible witnesses; any law or statute to the contrary notwithstanding."