- Apr 3 Conrad Veidt, German actor (Casablanca, Cabinet of Dr Calgary), dies from a heart attack at 50
- Apr 4 Oskar Schlemmer, German painter/sculptor, dies at 54
- Apr 4 Raoul Laparra, composer, dies at 66
- Apr 5 Aleš Hrdlička, Austro-Hungarian anthropologist and curator (US National Museum), dies at 74
- Apr 7 Jovan Ducic, Serbian poet (Blue Legends), dies at 72
- Apr 7 Alexandre Millerand, President of France (b. 1859)
- Apr 8 Paul Colin, Belgian journalist/collaborator, executed
- Apr 8 Richard Sears, 1st to win US amateur national tennis match, dies at 81
- Apr 14 Asser B Kleerekoper, SDAP-Second-Member of parliament, dies at 62
- Apr 14 Geoffrey Turton Shaw, composer, dies at 63
- Apr 15 Raffaele Casimiro Casimiri, composer, dies at 62
- Apr 15 Aristarkh Lentulov, Russian artist (d. 1882)
- Apr 18 I Yamamoto, admiral of Japanese fleet, dies
- Apr 19 Alexander Schmorell, German resistance fighter, beheaded
- Apr 19 Gustave Doret, composer, dies at 76
- Apr 19 Kurt Huber, German resistance fighter, beheaded
- Apr 19 Willy Graf, German resistance fighter, beheaded
- Apr 24 Gerardus H de Hare, socialist vicar, dies at 63
- Apr 25 Vladimir Ivanovich Nemirovich-Danchenko, playwright/director, dies
- Apr 29 Joseph Achron, Latvian violinist/composer (Golem suite), dies at 56
- Apr 29 Karl Adrian Wohlfart, composer, dies at 68
- Apr 29 Sidney A K Keyes, English poet (Foreign Gate), dies at 20
- Apr 30 Beatrice Potter Webb, British sociologist, economist ( founded London School of Economics) and writer (My Apprenticeship), dies at 85
- Apr 30 Etty Hillesum, Dutch diarist, dies in Auschwitz
- Apr 30 Otto Jespersen, Danish philologist (b. 1860)
- Apr 30 Leo Smit, Dutch composer, dies in Sobibór extermination camp at 42