- Main Article: Garfield's Mother
- Garfield's Mother (voiced by Sandi Huge) is the mother of Garfield and Raoul. She first appeared in the animated television special Garfield on the Town and later appeared in the special Garfield: His 9 Lives. She has also made a few cameos in the comic strip, including a December 1984 story, which was a loose adaptation of Garfield on the Town.
- Main Article: Garfield's Grandfather
- Garfield's Grandfather (voiced by C. Lindsay Workman) is the maternal grandfather of Garfield, Raoul, Sly and Garfield's other cousins, and the father of Garfield's Mother, Arno, Barney, Berle, Bernie, Bob, Ed, Edna, Evelyn, Harry, Hubert, Leo, Morty, Nick, Rockliva, Patrick, Roy and two unnamed sons. In both the comic strip and TV special continuity, Garfield's maternal granddad is a sulky and ill-tempered cat who continued to live in the Italian restaurant (which is Garfield's birthplace).
- Main Article: Raoul
- Raoul (voiced by George Wendt) is the half brother of Garfield.
- Main Article: Sly
- Sly (voiced by Gregg Berger) is one of the many cousins of Garfield.
- Great Grandfather Oslo was mentioned on the 30th of January, 1995. He was a pioneer. He moved his family thousands of miles across uncharted territory and kept saying, "I hear a can-opener.
- Garfield's grandfather
- In a stretch of 12 comics in November 1980 (excluding a Sunday), a different-looking Garfield's grandfather showed up in his house and told about things when he was young; then he left saying he would write Garfield letters. However, Garfield yelled "cats can't write" and his ancestor replied, "now you're getting the picture". In those comics, he had gray hair, a slim body shape and seemed to have a personality like Garfield. Possibly, that cat was Garfield's paternal grandfather shown only in those comic strips.
- Main Article: Great-Uncle Buchanan
- Great-Uncle Buchanan is Garfield's great-uncle and the first cat in space.Buchanan is identical to his great-grandson Garfield. As well as his appearance, his personality is likewise similar to that of Garfield.
The only mention of Great Uncle Ralph was on May 5th, 1988. It is claimed that he was a warthog.
There are also one unnamed great uncle who was mentioned on the 8th of February,1990. He was a lion. He was a big shot then, one day, he ate a sick monkey.
Aunt Edna was mentioned on the 10th of September, 1992 and the 3th of June, 1999. She used to say, "Let a smile be your umbrella," until her dentures were blown clean through the garage door by a bolt of lightning. She also married a hyena.
Aunt Evelyn was mentioned on the 10th of October, 1979. She plucked all her hair from her body to stop shedding. She currently resides in L.A., with a family that thinks that she is a chihuahua.
Aunt Reba was mentioned on the 6th of June, 1979. Garfield reacts with her name when Jon revealed that his tennis racket was strung with catgut.
Auntie Em has only been mentioned once on the 2d of February, 1987, after Garfield fell off a recliner and lost his memory, saying, "Auntie Em, is that you?", although this could be a side effect of the fall and/or a joke.
Uncle Ed was mentioned on the 19th April, 1989 and the 7th July, 1995 . He has been described as crazy,liked to sniff waffle irons, and his face was used for "Tic-Tac-Toe" games. He also always said, "Never belch out loud," and blew out an eyeball one day .
Uncle Barney was mentioned on 25th of June, 1975. He once went to the vet and came back as Garfield's Aunt Bernice.
Uncle Berle was mentioned on 17th of November, 1984. He is described as crazy, and thought that he was a dog. He always chased himself up trees and was constantly exhausted as a result.
Uncle Bernie was mentioned on 19th of September, 1988. He coined the phrases, "Never listen for a train by putting your ear on a train track.", and "Curiosity killed the cat.", in that order.
Uncle Bob was mentioned on the 26th of May, 1993. He used to say, "Slow down, take it easy." before being hit by a bus.
Uncle Arno was mentioned on 5th of March, 1990. Heis known for saying, "Life is like a festival; you have to get out there and enjoy it.". He was run over by a parade.
Uncle Harry was mensioned on the 23th of May, 1979. He lived in a glass plant in Gas City, Indiana. He was a famous mouser, eventually chasing a mouse into Tank #2. He is now a paperweight in Bayonne, New Jersey.
Uncle Hubert was mentioned on the 23th of June, 1979. He once caught a 30-pound canary in Chicago, and was last spotted over Dallas, Texas. For this reason, Garfield claims he does not chase birds. (comic June 23, 1979)
Uncle Leo was mentioned on the 28th of September, 2007, He always had a smile until an incident with denture weevils.
Uncle Morty was mentioned on the 16th of August, 1999. He was killed by his gluttony, after trying to take a papaya from a silverback gorilla.
Uncle Nick was mentioned on the 22d of March, 1983. He loved to destroy things and used to eat chickens whole. There are two conflicting statements to his current status. In one strip, it is said that he tried to swallow an ostrich after he mistook it for a chicken, with his last words being, "That's the biggest chicken I ever saw.". In another, it is stated that he is presently a postal employee in Chicago.
Uncle Patrick was mentioned on17th of May, 1985. He was famous for the quote, "I regret that I have but nine lives to give to my country."
Uncle Roy was mentioned on the 5th of Jenuary, 1982. He was said to be weird, he underwent a species change operation that transformed him into a dog; He later chased himself to death.
There are two unnamed uncles. One uncle was mentioned on August 18, 1987. He went to the vet once and had his brain replaced with that of a chicken. The rest of his life was spent sitting on eggs in grocery stores. Another uncle was mentioned on the 18th of August, 1987. He used to play with yarn, and is now a pattern in an angora sweater.
See also: Garfield's Family