| Election Name: | 1842 Boston mayoral election |
| Type: | Presidential |
| Ongoing: | no |
| Previous Election: | 1841 Boston mayoral election |
| Previous Year: | 1841 |
| Election Date: | December 12, 1842 |
| Next Election: | 1843 Boston mayoral election |
| Next Year: | 1843 |
| Image1: | Martin Brimmer 5210004 015 009 (3x4).jpg |
| Candidate1: | Martin Brimmer |
| Party1: | Whig Party (United States) |
| Popular Vote1: | 5,084 |
| Percentage1: | 61.86% |
| Candidate2: | Bradford Sumner |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 2,340 |
| Percentage2: | 28.47% |
| Mayor | |
| Before Election: | Jonathan Chapman |
| Before Party: | Whig Party (United States) |
| After Election: | Martin Brimmer |
| After Party: | Whig Party (United States) |
The 1842 Boston mayoral election saw the election of Whig Party nominee Martin Brimmer. It was held on December 12, 1842. Whig Party incumbent Jonathan Chapman was not a nominee for reelection.
Brimmer was the Whig Party nominee while Sumner was the Democratic Party nominee.[1] The Whigs did well in the coinciding municipal elections.[2]
Sumner had run for mayor in 1839 and for the United States House of Representatives in both 1838 and 1839.