- May 4 Charles Boucher de Boucherville, Premier of Quebec, born in Montreal, Quebec (d. 1915)
- May 10 August von Pettenkofen, Austrian outdoor painter, born in Vienna, Austria-Hungary (d. 1889)
- May 13 Francisco de Asís, Duke of Cádiz and King Consort of Spain (1846-68), born in the Royal Palace of Aranjuez, Spain (d. 1902)
- May 16 Eduard Hille, German composer and conductor, born in Wahlhauſen, Kingdom of Hanover (d. 1891)
- May 20 Emile Erckmann [co-wrote with Alexandre Chatrian using penname Erckmann-Chatrian], French writer (Waterloo), born in Meurthe, France (d. 1899)
- May 20 Frédéric Passy, French economist and pacifist (Nobel Peace Prize 1901 for European Peace Movement), born in Paris, France (d. 1912)
- May 21 Dabney Herndon Maury, American Major General (Confederate Army), born in Fredericksburg, Virginia (d. 1900)
- May 21 Mosby Monroe Parsons, United States officer in the Mexican–American War and brigadier general of the Confederate States Army, born in Charlottesville, Virginia (d. 1865)
- May 26 Edmond de Goncourt, French writer, wrote with his brother Jules de Goncourt, born in Nancy (d. 1896)
- May 27 Henry Wylde, English composer and conductor, born in Bushey, Hertfordshire, England (d. 1890)
- May 27 Joachim Raff, German-Swiss composer, born in Lachen, Switzerland (d. 1882)
20-29
30-39
40-49
50-59
80-89
Over 90