| John Marshall Eaton Jr. | |
| State House2: | Massachusetts |
| District2: | 13th Middlesex |
| Term Start2: | 1955 |
| Term End2: | 1964 |
| Birth Date: | March 26, 1918 |
| Birth Place: | Boston, Massachusetts, US |
| Death Date: | April 18, 1997 |
| Death Place: | Concord, Massachusetts, US |
| Alma Mater: | Harvard College (BA) Boston University School of Law (LLB) |
John Marshall Eaton Jr. (March 26, 1918 April 18, 1997) was an American politician who was the member of the Massachusetts House of Representatives from the 13th Middlesex district.[1]