The Northern Ireland Prison Service is the agency charged with managing prisons in Northern Ireland.
 It is an executive agency of the Department of Justice, the headquarters of which are in Dundonald House in the Stormont Estate in Belfast.
 The service's stated aim is "to improve public safety by reducing the risk of re-offending through the management and rehabilitation of offenders in custody".
 It is distinct from His Majesty's Prison Service, which manages most prisons in England & Wales, and the Scottish Prison Service, which manages most prisons in Scotland.
 The Prison Service is responsible for providing prison services in Northern Ireland. Its main statutory duties are set out in the Prison Act (Northern Ireland) 1953 and rules made under the Act.
 Prior to partition, prisons in Ireland were administered by the Prison Board of Ireland. After the Government of Ireland Act 1920, control of prisons in Northern Ireland was formally handed over from the Prison Board of Ireland on 1 December 1921 to the newly-created Northern Ireland Prison Service. The service was administered by the Ministry of Home Affairs, before being established as a government agency of the Northern Ireland Office on 1 April 1995, and later the Department of Justice following the devolution of justice powers on 12 April 2010.
 The Prison Service is a major component of the wider criminal justice system and contributes to achieving the system's overall aims and objectives. As the responsible Minister, Minister of Justice accounts to Northern Ireland Assembly for the Prison Service and shares Ministerial responsibility and accountability for the criminal justice system as a whole with the Attorney General. The office of Minister of Justice has been vacant since the collapse of the Northern Ireland Executive on 3 February 2022.
 As of March 2023, the Northern Ireland Prison Service employed 1,554 staff.
 The Prison Service currently has three operational establishments:
 A modern Category A prison housing adult male long-term sentenced and remand prisoners. Various units in the establishment also accommodate Category B and C prisoners.
 The prison also houses a working-out unit, where prisoners can leave the prison for short periods under direct supervision, and Burren House, a detachment of Maghaberry on Crumlin Road, Belfast, serves as a Category D unit.
 In accordance with the recommendations of the 2003 Steele Review, Maghaberry also runs a separated regime for paramilitary prisoners, with two wings specially adapted to house Loyalist and Republican prisoners.
 A medium-security prison housing shorter-term adult male prisoners which also has low-security accommodation for selected prisoners nearing the end of their sentences;
 Officially HM Prison Hydebank Wood, this is a medium-to-low-security establishment accommodating male young offenders and all female prisoners (including female immigration detainees).
 The service's primary Prison Officer training facility, the Prison Service College, is based at Hydebank Wood.
 Also known as Armagh Gaol, this establishment dates back to 1780, where it served as the primary women's prison in Northern Ireland for most of its life, although it held male prisoners at various points.
 The prison closed in 1986 and the female prisoners were moved to the newly-built Maghaberry Prison.
 Also known as Crumlin Road Gaol, this establishment opened in 1846 to replace the County Gaol for Antrim in Carrickfergus.
 The prison housed all categories of prisoners, many of which were imprisoned for Troubles-related crimes, and saw seventeen executions during its life.
 The prison closed in 1996 and the majority of prisoners were transferred to Maghaberry Prison.
 It now has a reputation for being a very paranormally-active location and the gaol runs its own guided ghost walks and paranormal investigations.
 This establishment began as Long Kesh Detention Centre in 1971, before being expanded with the building of the "H-blocks" in 1976 to become known as the Maze Prison.
 The most well-known prison during the Troubles, this establishment housed paramilitary prisoners from its formation, and was the scene of several infamous events such as the 1981 Hunger Strike and the Maze Prison escape of 1983.
 The prison was closed in 2000 and prisoners transferred to HMP Maghaberry. Demolition of most of the site began in 2006, but much of the western part of the estate remains, including the hospital block and H-block 6, which are listed structures. Plans to build a peace centre at the site broke down in 2019 when the European Union withdrew funding due to disagreements between the political parties. Unionist parties feared that the site could become a shrine to IRA members such as Bobby Sands, who died in the hospital block while on hunger strike.
 The site is now home to a number of organisations, such as the Ulster Aviation society, and the Balmoral Show.
 Much like officers of the Police Service of Northern Ireland, prison officers in Northern Ireland remain under a severe level of threat from dissident Republican terrorist groups, and - to a lesser extent - Loyalist paramilitary terrorist groups.
 Over thirty prison officers have been murdered in the line of duty in Northern Ireland, the vast majority by paramilitary terrorist groups. The most recent murders were that of David Black, shot dead on his way to work in 2012, and Adrian Ismay, who died in hospital eleven days after an IED detonated under his vehicle in 2016.
 Due to the ongoing threat, officers must inspect their vehicles each morning for IEDs, limit activities which may personally identify them, and be discreet about the display of uniform and other items which could identify them as prison officers. Officers may also avail of a personal protection weapon (PPW), although unlike their Police counterparts this is not mandatory.
 Prison officers in Northern Ireland wear a dark blue uniform (in contrast to the black uniform worn in England & Wales). The formal uniform consists of a white shirt, dark blue tie, dark blue tunic and trousers (for males) or skirt (for females), black shoes or boots, black gloves and a dark blue peaked cap for males and Kepi-style cap for females. Medals and a whistle on a chain are worn on the tunics.
For everyday use, the tunic is replaced with a fleece or NATO-style pullover. Tunics are no longer issued to new recruits and skirts are no longer issued to new female recruits, but both may still be used for some ceremonial duties.
 Prison officers in Hydebank do not wear a prison service uniform, but adopt instead a professional smart-casual dress code.
 In contrast to the Police Service of Northern Ireland, the Northern Ireland Prison Service maintains the Royal cypher on its cap badge, and the acronym "HMP" on its epaulettes.
 Prison officers (historically known as "warders"), under the Prison Act (Northern Ireland) 1953, have "all the powers, authority, protection and privileges of a constable" whilst acting as such.
 Prison Officers may carry weapons and use reasonable force (as sworn constables) to protect people. They carry expandable batons.
 Most prison officers work in teams or shifts, with a single unit (normally referred to as a House) overseen by a Senior Officer, and usually with three or four staff to a wing. Larger units such as Davis House may have three or four Senior Officers in command, and dozens of officers on the wings.
 The overall manager of a unit or house is the Unit Manager, a junior Governor grade, who has overall responsibility for their house and line management of the house Senior Officer.
 Prison officers working on landings will carry:
 Prior to 2012 the rank structure of the Northern Ireland Prison Service was similar to that of England and Wales pre-2000. The primary contingent comprised Main Grade Officers and Operation Support grades, subordinate to Principal Officers (rank badge – two Bath stars) and Senior Officers (rank badge – single Bath star).
 The Principal Officer grade was phased out between 2002 and 2008, and a new Senior Officer grade created in 2008 to streamline both roles. The custody Prison Officer grade was created in 2012 to replace Main Grades and Operation Support, although some longer-service staff remain in the older grades. The Unit Manager grade was created in 2014 as a junior Governor grade.
 The prison service currently has only two uniformed grades.
 Operational prison grades in descending order of rank are as follows:
 The Prisoner Escorting and Court Custody Service (PECCS), a subdivision of the prison service, maintains its own rank structure, which are as follows in descending rank order: