Results of the byelection for the Bromley Cross ward, held on October 28, 2021.
| Candidate | Description | Votes |
| ARMSTRONG, Laura Jane | Bolton for Change | 99 |
| COWEN, Amy Marie | The Conservative Party Candidate | 1,732 (elected) |
| HASLAM, James Peter | Liberal Democrats | 68 |
| MORT, Emily Grace Amelia | The Labour Party | 409 |
| SPENCER, Elizabeth Rosemary Clare | Green Party | 165 |