| Donald Buchanan Blue | |
| Constituency Mp: | Bruce |
| Parliament: | Canadian |
| Predecessor: | Andrew Ernest Robinson |
| Successor: | Andrew Ernest Robinson |
| Term Start: | June 27, 1949 |
| Term End: | August 9, 1953 |
| Birth Date: | May 6, 1901 |
| Birth Place: | Huron Township, Ontario, Canada |
| Party: | Liberal |
| Occupation: | auctioneer farmer merchant |
Donald Buchanan Blue (May 6, 1901 – December 4, 1974) was a Canadian politician, auctioneer, farmer and merchant. He was born in Huron Township, Ontario, Canada. He was elected to the House of Commons of Canada in the 1949 election as a Member of the Liberal Party to represent the riding of Bruce. He was defeated in the elections of 1953 and 1957.