Charles St. Clair Trainor (December 8, 1901 – June 19, 1978) was a lawyer, judge and political figure on Prince Edward Island.
He represented 5th Queens in the Legislative Assembly of Prince Edward Island from 1935 to 1939 as a Liberal.
He was born in Albany, Prince Edward Island, the son of Thomas Trainor and Annie Greenan, and was educated at Saint Dunstan's College.
In 1967, he was named to the Supreme Court of Prince Edward Island and became its chief justice in 1970.
He helped found the provincial polio association and was chairman of the Canadian National Institute for the Blind in the province.