- May 5 Karel Rudolph Gallas, Dutch lexicographer (French Dictionary), dies at 88
- May 7 Josef Hoffmann, Austrian architect (Vienna Secession Movement), dies at 85
- May 10 Clarence E. Mulford, American writer (Hopalong Cassidy), dies at 73
- May 11 Walter Sydney Adams, American astronomer and director of Mount Wilson, dies at 79
- May 12 Hendrik Marchant, Dutch politician (his private member's bill led to women's suffrage), dies at 87
- May 12 Louis Calhern, American actor (Julius Caesar; Blackboard Jungle), dies at 61
- May 12 Vladimír Ambros, Czech composer, dies at 65
- May 13 Aleksandr A. Fadejev, Russian author (Young Guard), commits suicide at 54
- May 14 Robert Willem Pieter Peereboom, Dutch editor in chief (Haarlem Newspaper), dies at 64
- May 15 Austin Osman Spare, English magician (b. 1886)
- May 16 H. B. Reese, American businessman, candy maker, and inventor (Reese's Peanut Butter Cups), dies of a heart attack at 76
- May 18 Maurice Tate, English cricket all-rounder (39 Tests, 155 wickets, 1 x 100, 5 x 50), dies at 60
- May 20 Andre Eugene Maurice Charlot, actor (Summer Storm), dies
- May 20 Max Beerbohm, English caricaturist, writer and parodist (Saturday Review), dies at 83
- May 24 Guy Kibbee, American actor (Capt Blood, Babes in Arms), dies at 74
- May 26 Al Simmons, American Baseball HOF outfielder (career BA .334; 3 × MLB All-Star; World Series 1929, 30; AL batting champion 1930, 31; Philadelphia A's), dies of a heart attack at 54
- May 29 Albert H. Edelkoort, Dutch theologist (Christusverwachting), dies at 65
- May 29 Hermann Abendroth, German conductor (Gewandhausorchester Leipzig, 1934-45), dies at 73
Assassination
Car Crash
Hanging
Killed in Action
Plane Crash
Poisoning