Robert Lyon (July 6, 1829 – 1888) was a judge and politician in the County of Carleton in eastern Ontario. He was mayor of Ottawa in 1867 and a Liberal member of the Legislative Assembly of Ontario from 1867 to 1871.
He studied law and was called to the bar in 1853. He began practicing law in Ottawa in 1856. He became an alderman and later mayor. Lyon also represented Carleton in the Ontario legislature from 1867 to 1871. He was named a judge for Carleton County in 1873.
- Historical Sketch of the County of Carleton (1971) - originally published in 1879, reprinted by Mika Press, Belleville, Ontario