Thomas Charles Cossitt (November 15, 1927 – March 15, 1982) was a Canadian politician.Born in Brockville, Ontario, the son of Edwin Comstock Cossitt and Marjorie Helen Delahaye, he graduated from St. Andrew's College and received a Bachelor of Arts degree from the University of Toronto. After graduating, he was the owner and president of an insurance company. He was president of the Eastern Ontario Liberal Federation and a vice-president of the Ontario Liberal Party.