- May 2 Désiré Charnay, French traveller and archaeologist, born in Fleurie, France (d. 1915)
- May 8 Henri Dunant, Swiss humanitarian, Founder of Red Cross (Nobel 1901), born in Geneva, Switzerland (d. 1910)
- May 8 Sharbel Makhluf, Lebanese Maronite monk, born in Bekaa Kafra, North Governorate, Lebanon (d. 1898)
- May 12 Gabriel Dante Rossetti, English Pre-Raphaelite figure poet and painter, born in London, England (d. 1882)
- May 19 Adin Ballou Underwood, American Brevet Major General (Union Army), born in Worcester County Massachusetts (d. 1888)
- May 20 James William Reilly, American lawyer, politician, and Brigadier General (Union Army), born in Akron, Ohio (d. 1905)
- May 22 Bartel Wilton, Dutch ship builder, born in Rotterdam (d. 1898)
- May 23 Edward Hitchcock Jr., 1st American physical educator (Amherst College), born in Amherst, Massachusetts (d. 1911)
- May 28 Alpheus Baker, American Brigadier General (Confederate Army), born in South Carolina (d. 1891)
20-29
30-39
40-49
50-59
80-89
Over 90