- Dec 3 MLB Rules Committee adopts a series of changes designed to increase amount of offensive run production; decreases strike zone size and lowers height of pitcher's mound from 15" to 10"; changes are successful
Esposito Scores on Brother's Debut
Dec 5 Future Hockey Hall of Fame center Phil Esposito of the Boston Bruins scores 2 goals in his goaltender brother Tony's (also HOF) NHL debut for the Montreal Canadiens; 2-2 tie
- Dec 6 Major League Baseball dismisses Commissioner William Eckert after 3 years
Frazier vs. Bonavena
Dec 10 Joe Frazier beats Oscar Bonavena in 15 for heavyweight boxing title
Ashe 1st Black No. 1
Dec 12 Arthur Ashe becomes 1st black person be ranked #1 in tennis
- Dec 24 Ballon d'Or: Manchester United's winger George Best wins award for best European football player ahead of teammate Bobby Charlton and Red Star Belgrade winger Dragan Džajić; first Northern Irish national to win the award
- Dec 26 Bruin Ted Green sets NHL penalty record of 3 minors, 2 majors & 2 game misconducts in a game against NY Rangers in NY's Madison Square Garden
- Dec 28 57th Davis Cup: USA beats Australia in Adelaide (4-1)
NY Jets Beat Oakland Raiders
Dec 29 AFL Championship, Shea Stadium, NYC: New York Jets beat Oakland Raiders 27-23; Joe Namath 3 TD passes sparks Jets to win
- Dec 29 NFL Championship, Cleveland Municipal Stadium: Baltimore Colts shutout Cleveland Browns, 34-0
- Dec 31 NY Jets win AFL championship