Donald MacKeen Smith (November 26, 1923 – February 16, 1998) was a Canadian politician. He represented the electoral districts of Halifax Centre and Halifax Citadel in the Nova Scotia House of Assembly from 1960 to 1970 as a member of the Progressive Conservatives. Born in 1923 at Halifax, Nova Scotia, Smith was educated at the University of King's College and Dalhousie University. He served with the 18th Armoured Car Regiment from 1944 to 1945. He married Helen Elizabeth Guildford in 1949. A business executive by career, Smith was president of J.E. Morse and Co. Ltd.