- Apr 1 Arnold Aletrino, Dutch physician, criminologist, and author (From Life), born in Amsterdam (d. 1916)
- Apr 1 Gaetano Mosca, Italian sociologist (Circulation of Elite), born in Palermo, Kingdom of the Two Sicilies (d. 1941)
- Apr 1 Truby King, New Zealand physician, pioneer in infant welfare (Karitāne hospitals, Plunket Society), born near New Plymouth, Zealand (d. 1938) [1]
Émile Durkheim (1858-1917)
Apr 15 French sociologist (De la division du travail social / The Division of Labour in Society), born in Épinal, France
- Apr 19 May Robson [Mary J Robison], Australian actress (Apple Annie), born in Moama, New South Wales, Australia (d. 1942)
- Apr 19 Siegfried Ochs, German composer, born in Frankfurt, Germany (d. 1929)
- Apr 20 Auguste Chapuis, French composer, born in Dampierre-sur-Salon, France (d. 1933)
- Apr 22 Ethel Smyth, English composer, born in Sidcup, Kent (d. 1944)
- Apr 23 Max Planck, German physicist, father of Quantum Physics (Planck Constant, Nobel 1918), born in Kiel, Duchy of Holstein (d. 1947)
- Apr 30 Mary Dimmick Harrison, US First lady (1889-93) as second wife of the 23rd President Benjamin Harrison, born in Honesdale, Pennsylvania (d. 1948)