- May 2 Karl Michael Ziehrer, Austrian composer, born in Vienna, Austria (d. 1922)
- May 6 Grove Karl Gilbert, American geologist (investigated Lake Bonneville, Utah), born in Rochester, New York (d. 1918)
- May 9 Isabella "Belle" Boyd, American actress and Confederate spy during US Civil War, born in Martinsburg, Virginia (d. 1900)
- May 10 Benito Pérez Galdós, Spanish novelist (Episodios Nacionales), born in Las Palmas, Spain (d. 1920)
- May 10 Kaufmann Kohler, German-born American reform rabbi and theologian, born in Fürth (d. 1926)
- May 13 Paul Smet de Naeyer, Belgian politician and count (Prime Minister of Belgium 1896-99, 1899-1907), born in Ghent, Belgium (d. 1913)
- May 20 Pedro Miguel Marques y Garcia, Spanish violinist and composer, born in Palma, Majorca (d. 1918)
- May 21 Charles-Albert Gobat, Swiss politician, recipient of the 1902 Nobel Peace Prize, born in Tramelan, Switzerland (d. 1914)
- May 21 Louis Renault, French lawyer, born in Autun, France (d. 1918)
- May 29 Émile Pessard, French pianist, concert and comic opera composer, and teacher (Maurice Ravel, Jacques Ibert), born in Paris (d. 1917)