- May 1 Prince Arthur, Duke of Connaught and Strathearn, Governor General of Canada (1911-16), born in Buckingham Palace, London (d. 1942)
- May 8 Ross Barnes, American baseball infielder (3×NA/NL batting champion 1872, 73, 76; 4×NA/NL runs scored leader; 4×NA/NL hits leader; Boston Red Stockings), born in Mount Morris, New York (d. 1915)
- May 10 Thomas Lipton, Scottish yachtsman (5-time America's Cup challenger) and tea merchant (Lipton Tea), born in Glasgow, Scotland (d. 1931)
- May 12 Henry Cabot Lodge, U.S. statesman, born in Beverly, Massachusetts (d. 1924)
- May 16 Arthur Henry Mann, organist/composer
- May 17 Antonio Scontrino, Italian composer, born in Trapani, Italy (d. 1922)
- May 18 Oliver Heaviside, English physicist (predicted ionosphere), born in London, England (d. 1925)
- May 20 Eaton Faning, composer
- May 21 Giuseppe Mercalli, Italian volcanologist (d. 1914)
- May 22 Johann Schrammel, Austrian composer, born in Vienna, Austria (d. 1893)
- May 24 Ernest Albert Waterlow, English water-color painter, born in London (d. 1919)
- May 27 Thomas Neill Cream, Scottish-Canadian serial killer (Lambeth poisoner), born in Glasgow, Scotland (d. 1892)