| William Nathanial Davenport | |
| Office: | 4th Mayor of Marlborough |
| Term Start: | 1887 |
| Term End: | 1887 |
| Predecessor: | John O'Connell |
| Successor: | Charles L. Bartlett |
| Birth Date: | November 3, 1856 |
| Birth Place: | Boylston, Massachusetts |
| Death Place: | Miami, Florida, US |
| Resting Place: | Boylston, Massachusetts |
| Office2: | Member of the Massachusetts Senate |
| Term Start2: | 1888 |
| Term End2: | 1889 |
| Office3: | Member of the Massachusetts House of Representatives |
| Term Start3: | 1886 |
| Term End3: | 1887 |
| Party: | Republican |
| Alma Mater: | University of Michigan School of Law |
| Occupation: | Lawyer |
| Spouse: | Lizzie M. Kendall |
William Nathanial Davenport (November 3, 1856 – January 28, 1933) was a Massachusetts, USA, politician who sat in both branches of the Massachusetts legislature, and was the fourth mayor of Marlborough, Massachusetts.
Davenport was born in Boylston, Massachusetts, on November 3, 1856, as the son of Almira J. Howard and William J. Davenport. He attended law school at the University of Michigan in Ann Arbor, Michigan. In 1887, he married Elizabeth Moore "Lizzie" Kendall (1862–1957). They lived in Marlborough and Worcester, Massachusetts.
Davenport was admitted to the Michigan Bar in 1882 and the Massachusetts Bar in 1883. From 1886 to 1887, he was a member of the Massachusetts House of Representatives. In 1887, he succeeded John O'Connell as the fourth mayor of Massachusetts. Following his tenure as mayor, he was elected to the Massachusetts Senate as a member of the 110th Massachusetts General Court.