| Election Name: | 1921 Hertford by-election |
| Type: | presidential |
| Country: | United Kingdom |
| Previous Election: | Hertford (UK Parliament constituency)#Elections in the 1910s |
| Previous Year: | 1918 |
| Next Election: | Hertford (UK Parliament constituency)#Elections in the 1920s |
| Next Year: | 1922 |
| Election Date: | 16 July 1921 |
| Candidate1: | Sueter |
| Party1: | Anti-Waste League |
| Popular Vote1: | 12,329 |
| Percentage1: | 68.9% |
| Candidate2: | Carlile |
| Party2: | Unionist Party (UK) |
| Popular Vote2: | 5,553 |
| Percentage2: | 31.1% |
| Map Size: | 250px |
| MP | |
| Posttitle: | Subsequent MP |
| Before Election: | Billing |
| Before Party: | Independent politician |
| After Election: | Sueter |
| After Party: | Anti-Waste League |
The 1921 East Hertfordshire division by-election was held on 16 July 1921. It had been necessitated by the resignation of the incumbent MP, Noel Pemberton Billing due to ill-health. The seat was gained from the Unionist Party by the Anti-Waste League.