A cat and Earl's best friend.
One of Mooch's owners and Millie's husband.
One of Mooch's owners and Frank's wife.
A tethered dog.
- Angry Guard Dog: Played with but generally averted - Guard Dog, while surly, rarely gets angry enough to threaten anyone. He's just as likely to elicit sympathy from being tied up all the time.
A Big Friendly Dog
who "wuvs" everything.
A tough alley cat.
Shtinky Puddin' (also known as Jules)
A little kitten and dedicated animal advocate.
The owner of the deli that Earl and Mooch often visit.
The world's crabbiest crustacean.
A grouchy cat who hates Mondays.
- Cats Are Mean: Probably the only cat character in the strip who plays it straight.
- Grumpy Bear: He's called Sourpuss for a reason.
- Meaningful Name: He's a cat. He's a grouch. In other words, he's a sourpuss.
Frank and Millie's pet goldfish.
The neighborhood's resident Cheerful Child
Bip and Bop
A pair of mischievous squirrels.
Chickpea and Chickpea's Brother
Two kittens that made their debut in a Shelter Stories arc.
A housecat and the object of Mooch's affections.
Chippy and Monk
A pair of chipmunks who are members of the Mutts Book Club.
A wise-crackling shellfish and Crabby's sidekick.
Mooch's pet snail.