1965–66 Boston Celtics season Game log December

| Game | Date_ | Opponent | Score | Location_Attendance | Record |
|---|---|---|---|---|---|
| 20 | December 3 | Philadelphia 76ers | 103–119 | Boston Garden | 14–6 |
| 21 | December 4 | @ St. Louis Hawks | 100–94 | St. Louis Arena | 15–6 |
| 22 | December 5 | @ Cincinnati Royals | 99–108 | Cincinnati | 15–7 |
| 23 | December 7 | St. Louis Hawks | 112–96 | New York, NY | 16–7 |
| 24 | December 8 | Los Angeles Lakers | 108–106 | Boston Garden | 17–7 |
| 25 | December 11 | San Francisco Warriors | 143–106 | Boston Garden | 18–7 |
| 26 | December 15 | Cincinnati Royals | 110–117 | Boston Garden | 18–8 |
| 27 | December 17 | @ Detroit Pistons | 114–112 | Detroit | 19–8 |
| 28 | December 22 | New York Knickerbockers | 123–120 | Boston Garden | 20–8 |
| 29 | December 25 | @ Baltimore Bullets | 113–99 | Baltimore | 21–8 |