Denis Allen (2 January 1896 – 29 March 1961) was an Irish revolutionary and politician.

[1] In the Truce period, he claimed in his military service pension file that he was promoted to Battalion Intelligence Officer at the time of the IRA split in March 1922 and Battalion Quartermaster from May 1922.

Taking the anti-Treaty side in the Irish Civil War (1922-1923), Allen claims that he took part in several armed operations against National Army troops.

Allen was arrested by the Free State on 4 August 1922; escaped from the Newbridge Camp, County Kildare on 15 October 1922; was re-arrested by the authorities on 20 October 1922 and escaped again on 19 November 1922 from Wexford.

In 1926 Allen was the Officer Commanding the North Wexford Battalion of the Irish Republican Army.