Floyd Duncan MacDonald (born November 6, 1934 - April 15, 2023) was a Canadian doctor and politician. He represented the electoral district of Queens in the Nova Scotia House of Assembly from 1971 to 1974. He was a member of the Nova Scotia Progressive Conservative Party.
MacDonald was born at Fredericton Junction, New Brunswick. He attended Acadia University and Dalhousie University, earning a M.D. degree from the latter. He resides in Hartland, New Brunswick.
MacDonald entered provincial politics in November 1971, winning a byelection for the Queens riding by 808 votes. He served one term and did not reoffer in the 1974 election.