- May 1 Alfred Napoleon Alexander "Natti" Duffié, French-American Brigadier General (Union Army), born in Paris, France (d. 1880)
- May 4 Edmund Hart Turpin, English composer, born in Nottingham, England (d. 1907)
- May 11 Kārlis Baumanis, Latvian composer (Dievs, svētī Latviju! (“God bless Latvia!”), the national anthem of Latvia), born in Viļķene Parish, Courland Governorate, Russian Empire (d. 1905)
- May 21 František Chvostek, Moravian physician (d. 1884)
- May 21 Newton Martin Curtis, American Brevet Major General (Union Army), born in De Peyster, New York (d. 1910)
- May 26 Edward Porter Alexander, Brigadier General (Confederate Army) and military engineer, born in Washington, Georgia (d. 1910)
- May 30 Alfred Austin, English poet laureate of England (Garden), born in Headingley, Yorkshire, England (d. 1913)
- May 31 Hijikata Toshizō, Japanese military leader, born in Hino, Tokyo, Japan (d. 1869)
20-29
30-39
40-49
50-59
80-89
Over 90