Elections to North Down Borough Council were held on 17 May 1989 on the same day as the other Northern Irish local government elections. The election used four district electoral areas to elect a total of 24 councillors. Prior to the election three Ulster Unionist politicians, including George Green, had defected to the Conservative Party in Northern Ireland. The election saw the Conservative presence in North Down doubling, with the Conservatives emerging as the single largest party on the council.