Mog
The title character. A shy, slightly absentminded but friendly cat who likes to eat eggs.
- Badass Unintentional: In "Mog the Forgetful Cat", she meows loudly to be let in, which ends up startling the burglar into dropping the bag of stuff, making a loud crash and getting himself arrested.
- Butt-Monkey: Zigzagged. She has both her lucky and her unlucky moments.
- Cat Up a Tree: Zigzagged in "Mog and the Granny" where she can't climb from the tree but can jump.
- The Ditz: Downplayed. While she is described as "not being very clever", she is more absent than actually stupid.
- Hidden Depths: A little cat... who can psychically locate one of her owners, once unintentionally led to a burglar's arrest, and even came back after apparently dying.
- Inexplicably Awesome: We don't know how she can find Debbie with her mind, she just can.
- Lovable Coward: Is a literal scaredy-cat and very sweet.
- Nightmare Sequence: In "Mog on Fox Night", she dreams that Mr. Thomas has thrown out all the eggs in the world.
- Out-of-Character Moment: Seems strangely antagonistic towards Debbie's friend Emily in "Mog's Amazing Birthday Caper".
- Phrase Catcher: Subverted. At first, Mr and Mrs Thomas used to say, "Bother that cat!" about her, but it's much rarer now.
- Psychic Powers: Can tell where Debbie is just by thinking about it.
- Unexplained Recovery: In "Goodbye, Mog" she appears to die, but in "Mog's Christmas Calamity" she's perfectly fine.
Debbie Thomas
The daughter of Mr and Mrs Thomas, one of Mog's owners and the older sister of Nicky. She is the closest one to Mog, always ready to defend her and becoming concerned about her the easiest.
- Birthday Episode: Has her birthday in "Mog's Amazing Birthday Caper".
- The Heart: Is the friendliest Thomas, although Nicky is a close second.
- Nightmare Sequence: In "Mog the Forgetful Cat", she has a nightmare where a tiger wants to eat her.
Nicky Thomas
The son of Mr and Mrs Thomas, younger brother of Debbie and one of Mog's owners. While not as much as Debbie, he is also affectionate towards Mog, although he's not as knowledgeable about cat care as her.
- Does Not Like Spam: He doesn't mind Mog eating his breakfast because, as Debbie pointed out, "Nicky doesn't like eggs anyway."
- Hair of Gold, Heart of Gold: A friendly little boy with blond hair.
- "Setting Off" Song: He wrote the "We're Going to America" song (about skyscrapers, sightseeing and different time zones) in "Mog and the Granny".
- Sick Episode: In "Mog and the Baby", he's said to have a cold but seems fine.
Mrs Thomas
The wife of Mr Thomas, mother of Debbie and Nicky, and one of Mog's owners. Sometimes can get angry at Mog but not as much as Mr Thomas.
Mr Thomas
The husband of Mrs Thomas, father of Debbie and Nicky, and one of Mog's owners. He seems to be the one who's most likely to antagonize Mog, but at the same time, he is by no means a villain.
- Jerk with a Heart of Gold: Sure, he's the most negative about Mog, but he's not bad at all. He's just as upset by her death in "Goodbye Mog" as the rest of the family.
- Temporarily Exaggerated Trait: It's not out-of-character for him to refer to Mog as "that cat", scold her or say she's misbehaving, but in "Mog's Bad Thing", he calls her horrible. Then again, peeing on his chair is probably the worst thing she's done.
