The Northern Ireland Public Service Alliance (NIPSA) is a trade union in Northern Ireland affiliated to the Irish Congress of Trade Unions. It is the largest trade union in Northern Ireland, with around 46,000 members, and is organised into two groups, the Civil Service Group, for the staff of public bodies employed on civil service terms and conditions, and the Public Officers Group, for employees of education and library boards, health and social services boards, the Northern Ireland Housing Executive, district councils, other public bodies and voluntary organisations.