Events in Sport
- May 9 56th Preakness: George Ellis aboard Mate wins in 1:59
- May 10 Golf ball size hail falls in Burlington, New Jersey
- May 16 57th Kentucky Derby: Charley Kurtsinger on Twenty Grand wins 2:01.8
Baseball Record
May 30 Phillies Chuck Klein homers off Ben Cantwell (Braves) in both ends DH

Chuck Klein
- May 30 Indianapolis 500: Louis Schneider wins in 5:10:27.948 (155.509 km/h)
- May 31 French Championships Men's Tennis: Jean Borotra wins his only home title; beats fellow Frenchman Christian Boussus 2-6, 6-4, 7-5, 6-4
French Open Women's Tennis
May 31 French Championship Women's Tennis: Cilly Aussem of Germany beats England's Betty Nuthall 8-6, 6-1 for the first of 2 major titles in 1931

Betty Nuthall
Birthdays in Sport
Willie Mays
May 6 Willie Mays, American Baseball Hall of Fame center fielder (24 x MLB All Star; 12 x Gold Glove Award; 660 career HRs, NL MVP 1954, 65; SF Giants, NY Mets), born in Westfield, Alabama

Willie Mays
- May 15 Ken Venturi, American golfer, broadcaster (US Open 1964), born in San Francisco, California (d. 2013)
- May 19 Bob Anderson, British racing driver (d. 1967)
- May 20 Chiharu Igaya, Japan, slalom (Olympic silver 1956)
- May 20 Ken Boyer, American baseball player (d. 1982)
- May 26 Jim Frey, American MLB manager (Kansas City Royals, American League C'ship 1980; Chicago Cubs), born in Cleveland, Ohio (d. 2020)
- May 28 Raymond Miquel, chairman (Scottish Sports Council)
Deaths in Sport
- May 5 Glen Kidston, British aviator and racing driver (b. 1899)