| Birthname: | John Sinclair Brown |
| Order1: | 45th |
| Office1: | Speaker of the Virginia House of Delegates |
| Term Start1: | January 8, 1930 |
| Term End1: | January 8, 1936 |
| Predecessor1: | Thomas W. Ozlin |
| Successor1: | Ashton Dovell |
| Office2: | Member of the Virginia House of Delegates from Roanoke County |
| Term Start2: | January 12, 1916 |
| Term End2: | January 8, 1936 |
| Predecessor2: | Orren L. Stearnes |
| Successor2: | Benjamin E. Chapman |
| Birth Date: | 30 September 1880 |
| Death Place: | Salem, Virginia, U.S. |
| Party: | Democratic |
| Spouse: | Jane Lewis Johnston |
John Sinclair Brown (September 30, 1880 – January 15, 1965) was a Virginia politician. He represented Roanoke County in the Virginia House of Delegates, and served as that body's Speaker from 1930 until 1936.
Brown Library, built in 1969, is the main academic library at Virginia Western Community College in Roanoke, Virginia and was named for Colonel Brown in recognition of his service to the Roanoke Valley community.