Mimmy (ミミィ, Mimyi) is Hello Kitty's adorable and very beautiful twin sister and playmate. Mimmy wears a yellow bow on her left ear while Kitty wears a red bow on her right and is also mouthless like her sister. Mimmy seems to have a slightly less outgoing, but more polite and thoughtful personality than Kitty does, and they seem to highly enjoy each other's company. Anyone would describe Mimmy as shy and very girly.
Mimmy's hobbies include sewing and dreaming of marriage.
Mimmy is the twin of Hello Kitty. She also has a mom and a dad. Her grandma and grandpa are also often shown. They live in London in a small house. Mimmy is not only Hello Kitty's sister, but also her best friend.