Don or Donald McKenzie (also Mackenzie or MacKenzie) may refer to:

Donald Gordon McKenzie (April 9, 1887—May 14, 1963) was a politician in Manitoba, Canada. He served in the Legislative Assembly of Manitoba from 1928 to 1936 and was a cabinet minister in the government of John Bracken.

McKenzie was born in Brandon, Manitoba, to parents who were recent settlers from Huron County, Ontario. His father, Roderick McKenzie, was a founder and for years a prominent member of the farmers' movement in Western Canada.

The younger McKenzie was educated at Brandon Collegiate and Manitoba Agricultural College, and himself worked as a farmer. He married Katie Belle Cole in 1914. He was a member of United Grain Growers Ltd. of Winnipeg, and secretary-treasurer of the local United Farmers of Manitoba division from 1922 to 1926. From April 1926 to October 1928, he served as part of an advisory board on Tariff and Taxation.

Although he had no prior experience in electoral politics, McKenzie was appointed to John Bracken's government on October 22, 1928 as Minister of Mines and Natural Resources. On November 10, 1928, he was elected to the Manitoba legislature in a by-election in the constituency of Lansdowne, replacing former Premier Tobias Norris. McKenzie ran as a "Liberal-Progressive", and was endorsed by both Bracken's Progressives and the local branch of the Manitoba Liberal Party.

Donald Ward McKenzie, Jr. (May 11, 1947 – December 3, 2008) was an American competition swimmer, Olympic champion, and former world record-holder.

McKenzie attended Indiana University, where he swam for coach Doc Counsilman's Indiana Hoosiers swimming and diving team in National Collegiate Athletic Association (NCAA) competition during the late 1960s. He won an individual NCAA national championship in the 100-yard breaststroke while swimming for the Hoosiers.

He competed at the 1968 Olympic Games in Mexico City, where he received a gold medal for winning the men's 100-meter breaststroke. He won a second gold medal as a member of the winning U.S. team in the men's 4×100-meter medley relay. The first-place team of Charlie Hickcox, McKenzie, Doug Russell and Ken Walsh set a new world record time of 3:54.9 in the event final.

McKenzie was inducted as an "Honor Swimmer" into the International Swimming Hall of Fame in 1989. In 2000, he was inducted into the Indiana University Hall of Fame. He was also inducted posthumously into the Los Angeles Valley College Athletic Hall of Fame in 2011.