Elections to Castlereagh Borough Council were held on 21 May 1997 on the same day as the other Northern Irish local government elections.

The election used four district electoral areas to elect a total of 23 councillors.

Note: "Votes" are the first preference votes.

1993: 4 x DUP, 1 x Alliance, 1 x UUP, 1 x Independent Unionist 1997: 4 x DUP, 1 x Alliance, 1 x UUP, 1 x UKUP 1993-1997 Change: Independent Unionist joins UKUP 1993: 3 x DUP, 1 x Alliance, 1 x UUP, 1 x UPUP, 1 x Independent Unionist 1997: 4 x DUP, 1 x Alliance, 1 x UUP, 1 x Independent Unionist 1993-1997 Change: UPUP joins DUP 1993: 2 x UUP, 2 x Alliance, 1 x DUP 1997: 2 x UUP, 1 x Alliance, 1 x DUP, 1 x SDLP 1993-1997 Change: SDLP gain from Alliance 1993: 2 x UUP, 2 x DUP, 1 x Alliance 1997: 2 x DUP, 1 x UUP, 1 x Alliance, 1 x SDLP 1993-1997 Change: SDLP gain from UUP