Elections to Castlereagh Borough Council were held on 7 June 2001 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.

1997: 4 x DUP, 1 x Alliance, 1 x UUP, 1 x UKUP 2001: 4 x DUP, 1 x Alliance, 1 x UUP, 1 x PUP 1997-2001 Change: PUP gain from UKUP 1997: 4 x DUP, 1 x UUP, 1 x Alliance, 1 x Independent Unionist 2001: 4 x DUP, 1 x UUP, 1 x Alliance, 1 x Independent 1997-2001 Change: Independent gain from Independent Unionist 1997: 2 x UUP, 1 x DUP, 1 x SDLP, 1 x Alliance 2001: 2 x UUP, 1 x DUP, 1 x SDLP, 1 x Alliance 1997-2001 Change: No change 1997: 2 x DUP, 1 x UUP, 1 x SDLP, 1 x Alliance 2001: 2 x DUP, 1 x UUP, 1 x SDLP, 1 x Alliance 1997-2001 Change: No change