- May 7 Gerhard Moritz Roentgen, Dutch industrialist (founder of Fijenoord dockyard), born in Esen, East Frisia (d. 1852)
- May 10 Jacques-Nicolas-Augustin Thierry, French historian, born in Blois, France (d. 1856)
- May 13 Gérard Paul Deshayes, French geologist (d. 1875)
- May 13 Joshua Ratoon Sands, American Rear Admiral (Union Navy), born in Brooklyn, New York (d. 1883)
- May 15 Adolf B Marx, German music theorist
- May 19 Johns Hopkins, philanthropist, founded Johns Hopkins University
- May 23 Charles Barry, British architect, born in London (d. 1860)