Jay R. Cat - Jay is a rainbow cat, possibly a mix of Tom Cat and Butch.
BlackBulldog - BlackBulldog (occasionally referred to as Marth or MilkyBulldog) is a black and grey bulldog. His son is WhiteDog. BlackBulldog is very protective towards his son and gets very angry at RedCat if WhiteDog is bothered or harmed.
WhiteDog - WhiteDog is BlackBulldog's son.
GreyCat - GreyCat is a grey and white cat and is Tom Cat's father.
PinkCat - PinkCat is an attractive pink female cat, and is supposedly RedCat's usual love interest.
Lia Two-Shoes - From the beginning, RedCat also has to deal with Lia Two-Shoes, an European domestic housemaid.
YellowMouse - YellowMouse is a yellow mouse who is close to GreenMouse and appears frequently with him. He is sometimes seen as GreenMouse's nephew, but occasionally referred to as an orphan. In many cartoons, YellowMouse is seen eating a lot (he's always hungry).
GoldenDuck - Another recurring character, GoldenDuck the golden duckling.
FastCat - In some episodes, he is refered to one of RedCat's alley cat friends, but Lia Two-Shoes adopted him first.
BlackCat - BlackCat is usualy in love with PinkCat, but RedCat doesn't like it, so he is RedCat's nemesis. Sometimes he's a friend.
SlowCat - SlowCat is a navy blue cat with a purple hair and is one of RedCat's alley cat friends.
VioletCat - VioletCat is a violet and small cat and is one of RedCat's alley cat friends.
BlueBird - BlueBird is a bird who helps GreenMouse, but also attacks RedCat.
StrongMouse - StrongMouse is GreenMouse's cousin. He hurts RedCat when he bothers GreenMouse all the time.
WeakCat - WeakCat is RedCat's scaredy cousin. Mice frighten him.