- December 1, 1978:
- December 2, 1978: (The end of a storyline about Garfield getting a cold.)
- December 3, 1978:
- December 4, 1978:
- December 5, 1978:
- December 6, 1978:
- December 7, 1978:
- December 8, 1978:
- December 9, 1978:
- December 10, 1978:
- December 11, 1978: (The start of a storyline about Garfield shedding.)
- December 12, 1978:
- December 13, 1978:
- December 14, 1978:
- December 15, 1978:
- December 16, 1978: (The end of a storyline about Garfield shedding.)
- December 17, 1978:
- December 18, 1978:
- December 19, 1978: (The first non-three panel daily strip.)
- December 20, 1978:
- December 21, 1978:
- December 22, 1978: (The first of four Christmas strips.)
- December 23, 1978:
- December 24, 1978: (The first appearance of Santa Claus.)
- December 25, 1978: (Christmas Day and the last of four Christmas strips.)
- December 26, 1978:
- December 27, 1978:
- December 28, 1978: (This strip is animated in Here Comes Garfield.)
- December 29, 1978:
- December 30, 1978:
- December 31, 1978: (The last strip of 1978.)
| ← Garfield, November 1978 | Garfield, January 1979 → |