| Election Name: | 1874 Mayo by-election |
| Country: | United Kingdom |
| Turnout: | 54.4% |
| Next Year: | 1880 |
| Type: | parliamentary |
| Ongoing: | no |
| Previous Election: | 1874 United Kingdom general election |
| Previous Year: | 1874 (GE) |
| Election Date: | 29 May 1874 |
| Next Election: | 1880 United Kingdom general election |
| Seats For Election: | Constituency of Mayo |
| Candidate1: | George Eakins Browne |
| Image1: | HRL |
| Party1: | Home Rule League |
| Popular Vote1: | 1,330 |
| Percentage1: | 33.9% |
| Candidate2: | John O'Connor Power |
| Party2: | Home Rule League |
| Popular Vote2: | 1,319 |
| Percentage2: | 33.6% |
| Image3: | HRL |
| Candidate3: | Thomas Tighe |
| Party3: | Home Rule League |
| Popular Vote3: | 1,279 |
| Percentage3: | 32.6% |
| MPs | |
| Before Election: | George Eakins Browne Thomas Tighe |
| Before Party: | Home Rule League |
| After Election: | George Eakins Browne John O'Connor Power |
| After Party: | Home Rule League |
| Registered: | 3,608 |
The 1874 Mayo by-election was fought on 29 May 1874. The by-election was fought due to the void elections of the incumbent Home Rule MPs, George Ekins Browne and Thomas Tighe. George Eakins Browne was re-elected while Thomas Tighe was defeated by John O'Connor Power.