Frederick McIntosh Cass Q.C., C.D. was a Canadian politician who served as both Attorney-General of Ontario and Speaker of the Legislative Assembly. He served as a Progressive Conservative Member of Provincial Parliament from 1955 until his retirement in 1971. Cass served in the Canadian Army during the Second World War from 1941 to 1945.

The Attorney General of Ontario is the chief legal adviser to His Majesty the King in Right of Ontario and, by extension, the Government of Ontario. The Attorney General is a senior member of the Executive Council of Ontario and oversees the Ministry of the Attorney General – the department responsible for the oversight of the justice system in the province of Ontario. The Attorney General is an elected Member of Provincial Parliament who is appointed by the Lieutenant Governor of Ontario on the constitutional advice of the Premier of Ontario.