George Greenfield Macdonell (June 4, 1808–before 1878) was from a prominent family in Upper Canada. He was the first son of Alexander Macdonell of Greenfield, a nephew of John Macdonell of Greenfield and Donald Macdonell of Greenfield, and a great-nephew of Sir Hugh MacDonell of Aberchalder and John McDonell of Aberchalder. In 1841 George married Sarah Chesley, daughter of John Chesley and niece of Solomon Yeomans Chesley.