James Thomas Hammill Regan (June 29, 1855 – 1927) was a farmer, merchant and political figure in Ontario. He represented Wentworth South in the Legislative Assembly of Ontario from 1911 to 1919 as a Conservative member. He was born in Chatham, the son of James Regan and Sarah Hammill, and was educated in Ancaster and Dundas. Regan was married twice: first to Alferetta Templer in 1884 and then to Kate Alma Gabel in 1898. He ran unsuccessfully for a seat in the assembly in 1905 and 1908. Regan later served as sheriff for Wentworth County.