Social Democratic Party By-elections
| Election | Constituency | Candidate | Vote count | Vote share | Position |
| 20 July 2023 | Uxbridge and South Ruislip | Steve Gardner | 248 | 0.8% | 6th |
| 20 July 2023 | Selby and Ainsty | John Waterston | 314 | 0.9% | 8th |
| 15 December 2022 | Stretford and Urmston | Julien Yvon | 74 | 0.4% | 9th |
| 1 July 2021 | Batley and Spen | Oliver Purser | 66 | 0.2% | 14th |
| 13 May 2021 | Airdrie and Shotts | Neil Manson | 151 | 0.7% | 5th |
| 6 May 2021 | Hartlepool | David Bettney | 104 | 0.3% | 15th |
| 6 June 2019 | Peterborough | Patrick James O'Flynn | 135 | 0.4% | 9th |
| 4 April 2019 | Newport West | Ian Andrew McLean | 202 | 0.9% | 9th |