| John Sylvester Ross | |
| Office1: | Member of the Legislative Assembly for Dundas |
| Term Start1: | 1861 |
| Term End1: | 1866 |
| Predecessor1: | James William Cook |
| Successor1: | Position terminated |
| Office2: | Member of Parliament for Dundas |
| Term Start2: | 1867 |
| Term End2: | 1872 |
| Predecessor2: | Position established |
| Successor2: | William Gibson |
| Office3: | Member of Parliament for Dundas |
| Term Start3: | 1879 |
| Term End3: | 1882 |
| Predecessor3: | William Gibson |
| Successor3: | Charles Erastus Hickey |
| Party: | Conservative |
| Birth Date: | 16 June 1821 |
| Birth Place: | Osnabruck Township |
| Death Place: | Iroquois, Ontario |
| Occupation: | Miller, politician, merchant |
| Spouse: | Charlotte Carman |
| Children: | Hugo Homer Ross |
| Allegiance: | Canadian Militia |
| Battles: | Trent Affair (1862) |
| Rank: | Captain |
John Sylvester Ross (July 16, 1821 – July 1, 1882) was a miller and political figure in Ontario. He was a Liberal-Conservative member of the House of Commons of Canada who represented Dundas from 1867 to 1872 and from 1879 to 1882.
He was born in Osnabruck Township Upper Canada in 1821, the son of Michael Ross,[1] and settled in the village of Iroquois where he set up a general store. He married Charlotte Carman, the granddaughter of Peter Shaver, in 1845. Ross served on the council for Matilda Township and was reeve in 1856. In 1861, he was elected to the Legislative Assembly of the Province of Canada representing Dundas; he was reelected in 1863. He was president of the Iroquois Milling Company.[2] Ross was also secretary-treasurer and president for the High School Board.[1] He died in Iroquois at the age of 61.[3]
His son Hugo also represented Dundas in the House of Commons.