- May 1 US general strike for 8-hour working day begins
- May 3 M A Maclean elected 1st mayor of Vancouver, British Columbia
- May 4 Haymarket riot in Chicago; bomb kills 7 policemen
- May 5 The Bay View Tragedy occurs, as militia fires upon a crowd of protesters in Milwaukee, Wisconsin killing seven.
- May 8 Jacob's Pharmacy in Atlanta sells the first Coca-Cola (contained cocaine)
- May 14 12th Kentucky Derby: Paul Duffy aboard Ben Ali wins in 2:36.50
Event of Interest
May 15 British sailor David Beatty is promoted to midshipman

David Beatty
Event of Interest
May 29 American chemist John Pemberton begins to advertise Coca-Cola

John Pemberton