- May 10 John Wesley Hyatt, American inventor who simplified the production of celluloid, dies at 82
- May 11 William D Howells, American author (A Woman's Reason), dies at 83
- May 16 Levi P. Morton, United States Vice President under Benjamin Harrision (b. 1824)
- May 17 Maitland Hathorn, South African cricketer (325 runs in 12 Tests South African 1901-11), dies at 42
- May 21 Venustiano Carranza, Mexican President (1917-1920), executed by army generals after his decision that the next President be a civilian (61)
- May 23 Svetozar Boroević, Austrian field marshal (b. 1856)