This is a timeline of actions by the Official Irish Republican Army (Official IRA or OIRA), an Irish republican & Marxist-Leninist paramilitary group. Most of these actions took place as part of a Guerrilla campaign against the British Army & Royal Ulster Constabulary and internal Irish Republican feuds with the Provisional IRA & Irish National Liberation Army from the early 1970s - to the mid-1970s during the most violent phase of "the Troubles" in Northern Ireland.

Some members of the OIRA broke away to form the Official Republican Movement (ORM). The ORM members were angry with the lack of support the Workers Party gave to OIRA prisoners.^{[citation needed]}