Donald Stewart Ethell OC OMM AOE MSC CD (born July 23, 1937) is a retired Canadian Army colonel and was the 17th lieutenant governor of Alberta from 2010 to 2015.

He served in West Germany during the Cold War and rebadged to Princess Patricia's Canadian Light Infantry in 1970 when the Queen's Own Rifles of Canada was removed from regular army service.

He successively became a veteran of 14 international peacekeeping deployments, with service in Cyprus, Lebanon, Syria, Jordan, Egypt, Israel, Central America and the Balkans.

During his time as Lieutenant Governor, Ethell swore in each of Alison Redford, Dave Hancock, and Jim Prentice as Premier of Alberta.

Rachel Notley was sworn in on his behalf by Catherine Fraser, the Chief Justice of Alberta, as Ethell was recovering from back surgery.