Elections to Brentwood Borough Council were held on 1 May 2003. One third of the council was up for election, all seats last being elected in 2002 following boundary changes. Twelve years of Liberal Democrat control ended with the council passing into no overall control.
After the election, the composition of the council was
The swing was 5.5% from the Liberal Democrats to the Conservatives.
| Ward | Party | Incumbent Elected | Incumbent | Stood? | |
|---|---|---|---|---|---|
| Brentwood North | Liberal Democrats | 2002 | Reg Straw | Reelected | |
| Brentwood South | Liberal Democrats | 2002 | Margaret Hogan | Yes | |
| Brentwood West | Liberal Democrats | 2002 | Allan Wheatley | Reelected | |
| Brizes & Doddinghurst | Liberal Democrats | 2002 | Colin Brown | Reelected | |
| Herongate, Ingrave & West Horndon | Liberal | 2002 | Roy Boggis | Yes | |
| Hutton East | Liberal Democrats | 2002 | Stephen Tilley | Yes | |
| Hutton North | Conservative | 2002 | Dudley Payne | Reelected | |
| Ingatestone, Fryerning & Mountnessing | Conservative | 2002 | Sarah Courage | Reelected | |
| Pilgrims Hatch | Liberal Democrats | 2002 | Charles Myers | Reelected | |
| Shenfield | Conservative | 2002 | Philip Baker | Reelected | |
| Tipps Cross | Conservative | 2002 | Madeline Henwood | Reelected | |
| Warley | Liberal Democrats | 2002 | Jill Hubbard | Reelected |