Josiah Johnston Preston (June 7, 1855 – July 10, 1937) was an Ontario merchant and political figure.
He represented Durham East in the Legislative Assembly of Ontario from 1902 to 1919 as a Conservative member.
He was born in Manvers Township, Durham County, Canada West, the son of James Preston.
He served as reeve for Manvers and was also warden for the United Counties of Northumberland and Durham in 1897.
This article about an Ontario Progressive Conservative Party MPP is a stub.