John Ira Flatt (July 2, 1834 – November 26, 1913) was an Ontario farmer, merchant and political figure.
He represented Wentworth North in the Legislative Assembly of Ontario from 1894 to 1898 as a Liberal member.
He was born in East Flamborough, Wentworth County, Upper Canada in 1834, the son of Robert Flatt, a Scottish immigrant.
Flatt was involved in the timber trade, partnering with Robert Thompson until 1876 and then with a Mr.
Bradley.
The firm, originally based in the Hamilton area, later opened a branch at Casselman.
In 1853, he married Rachel Cummings.
With his sons, Jacob and William, he also was involved in a timber company operating in Michigan and Ohio.
Flatt served on the councils for East and West Flamborough and was also warden for Wentworth County in 1888.