The Elected Authorities (Northern Ireland) Act 1989 is an Act of the Parliament of the United Kingdom. It brought in a law that required candidates standing for election in Northern Irish local and Northern Ireland Assembly elections to declare they would not, by word or deed, express support for or approval of proscribed organisations or acts of terrorism (that is to say, violence for political ends). It had the effect of disqualifying numerous candidates in the 1989 Northern Ireland local government elections, particularly 23 candidates of the Republican Sinn Féin (RSF).