- December 1, 1980: (Start of Garfield's bored week.)
- December 2, 1980:
- December 3, 1980:
- December 4, 1980:
- December 5, 1980:
- December 6, 1980:
- December 7, 1980:
- December 8, 1980: (End of Garfield's bored week.)
- December 9, 1980: (The start of storyline about Jon planning to declaw Garfield for the second time.)
- December 10, 1980:
- December 11, 1980:
- December 12, 1980:
- December 13, 1980: (The end of storyline about Jon planning to declaw Garfield for the second time.)
- December 14, 1980:
- December 15, 1980:
- December 16, 1980:
- December 17, 1980: (The first appearance of Arlene and the start of an "Arlene week".)
- December 18, 1980:
- December 19, 1980:
- December 20, 1980: (End of an "Arlene week".)
- December 21, 1980: (The first atypical size Garfield comic strip.)
- December 22, 1980:
- December 23, 1980:
- December 24, 1980: (The start of Christmas comics.)
- December 25, 1980: (Christmas Day and the end of the Christmas comics.)
- December 26, 1980:
- December 27, 1980:
- December 28, 1980: (Most of the strip's dialogue is used in Here Comes Garfield.)
- December 29, 1980:
- December 30, 1980:
- December 31, 1980: (The last comic strip of 1980.)
| ← Garfield, November 1980 | Garfield, January 1981 → |