| Reuben Foster | |
| Order1: | Member of the Maine House of Representatives |
| Term Start1: | 1866 |
| Term End1: | 1867 |
| Order2: | Member of the Maine House of Representatives |
| Term2: | 1870 |
| Order3: | Member of the Maine Senate |
| Term Start3: | 1871 |
| Term End3: | 1872 |
| Order4: | Mayor of Waterville, Maine |
| Term Start4: | 1888 |
| Term End4: | 1888 |
| Predecessor4: | Position created |
| Successor4: | Nathaniel Meader |
| Birth Date: | February 7, 1833 |
| Birth Place: | Bethel, Maine |
| Death Date: | October 12, 1898 (aged 65) |
| Party: | Republican |
| Residence: | Waterville, Maine |
| Alma Mater: | Colby College |
| Occupation: | Lawyer |
Reuben Foster (February 7, 1833 – October 12, 1898) was an American politician and lawyer from Maine. Foster, a Republican, served three single-year terms in the Maine House of Representatives (1866-1867; 1870) and two single-year terms in the Maine Senate (1871-1872). In 1870, he was elected House Speaker and in 1872, he was elected Senate President.
In 1888, Waterville was incorporated as a city and elected Reuben Foster as its first mayor.
Foster was born in Bethel, Maine and graduated from Colby College in 1855. He practiced law in Waterville from 1858 until his death in 1898.[1]