- May 6 104th Kentucky Derby: Steve Cauthen wins aboard Affirmed - first and only Derby victory and 1st-leg of Triple Crown
- May 10 22nd European Cup: Liverpool beats Club Brugge 1-0 at London
- May 17 Los Angeles Dodgers Lee Lacy hits record 3rd consecutive pinch-hit home run
- May 20 103rd Preakness: Steve Cauthen wins aboard Affirmed for the 2nd-leg of the Triple Crown
- May 23 AL approves transfer of Red Sox to Jean Yawkey for $15M
- May 25 Stanley Cup Final, Boston Garden, Boston, MA: 3-peat for Montreal Canadiens; beat Boston Bruins, 4-1 as Mario Tremblay scores twice; 4-2 series victory