Elections to North Down Borough Council were held on 20 May 1981 on the same day as the other Northern Irish local government elections.

The election used four district electoral areas to elect a total of 20 councillors.

Note: "Votes" are the first preference votes.

1977: 2 x Alliance, 1 x UUP, 1 x UPNI, 1 x Independent Unionist 1981: 1 x Alliance, 1 x UUP, 1 x UPNI, 1 x DUP, 1 x Independent Unionist 1977-1981 Change: DUP gain from Alliance 1977: 2 x UUP, 1 x DUP, 1 x Alliance, 1 x Vanguard 1981: 2 x DUP, 2 x UPUP, 1 x Alliance 1977-1981 Change: UPUP (two seats) and DUP gain from UUP (two seats) and Vanguard 1977: 2 x Alliance, 2 x UUP, 1 x Vanguard 1981: 2 x Alliance, 1 x UUP, 1 x UPUP, 1 x DUP 1977-1981 Change: UPUP and DUP gain from UUP and Vanguard 1977: 2 x UUP, 2 x Alliance, 1 x UUUP 1981: 2 x UUP, 2 x Alliance, 1 x DUP 1977-1981 Change: DUP gain from UUUP