| James Sinclair Smith | |
| Office1: | Ontario MPP |
| Term Start1: | 1867 |
| Term End1: | 1874 |
| Predecessor1: | Riding established |
| Successor1: | John McDougall |
| Constituency1: | Middlesex North |
| Party: | Liberal |
| Birth Date: | 27 December 1816 |
| Birth Place: | Caithness, Scotland |
| Death Place: | McGillivray Township, Ontario |
| Occupation: | Farmer |
| Relations: | Alexander Smith, son |
James Sinclair Smith (December 27, 1816 - October 4, 1897) was a farmer, livestock breeder and political figure in Ontario, Canada.[1] He represented Middlesex North in the Legislative Assembly of Ontario as a Liberal member from 1867 to 1874.
He was born in Caithness, Scotland in 1816. He served as reeve of McGillivray Township in Middlesex County.[1] He was defeated by John McDougall in the 1875 general election.
Smith was postmaster at Maple Lodge in Middlesex County.
His son Alexander served in the Canadian House of Commons.[2] He died (supposedly) at McGillivray in 1897.[3]