- Dec 4 2nd NY Knicks game postponed (due to death of opponent 76ers' owner)
Masanori Murakami
Dec 4 San Francisco Giant Masanori Murakami, 4-1 this year, does not renew his contract signing instead with the Nankai Hawks of Osaka for $40,000
Robinson to Baltimore Orioles
Dec 9 Frank Robinson is traded from the Cincinnati Reds to the Baltimore Orioles
- Dec 10 Test Cricket debut of Doug Walters v England at the Gabba
Sayers Touchdown Record
Dec 12 Chicago halfback Gale Sayers ties NFL record for most touchdowns in a game with 6 in 61–20 victory over San Francisco 49ers at Wrigley Field
- Dec 12 Doug Walters makes maiden Test ton in 1st Test, goes on to 155
- Dec 15 William Eckert replaces Ford Frick as 4th Commissioner of Baseball
- Dec 26 AFL Championship, Balboa Stadium San Diego: Buffalo Bills beat San Diego Chargers 23-0; repeat previous year's win over SD
- Dec 28 Ballon d'Or: Benfica striker Eusébio wins award for best European football player; first Portuguese national to win, and still only Benfica player
Australia Win Over Spain
Dec 28 Davis Cup Men's Tennis, Sydney: John Newcombe & Tony Roche beat José Luis Arilla & Manuel Santana of Spain 6-3, 4-6, 7-5, 6-2 to give Australia unassailable 3-0 lead; ends 4-1
- Dec 29 CBS purchases NFL TV rights for 1966-68 at $18.8 million per year
Baseball Players
Basketball Stars
Boxers
Footballers
NFL Stars
Tennis Champions