Like all the members of Kikitchi's family, Mademoiselle Koko resembles a monkey. Her body is mostly purple, but her face is a light cream color. She has pink cheeks, a cat-like mouth, half-lidded eyes with pink eyeshadow, and a mole beneath her left eye. She wears a pink turban with white pearl-like decorations, orange and yellow earrings, and a pink dress with a fluffy white collar. In her official art she wears black stockings, but her DS sprite depicts her with purple legs. She also appears to carry some kind of pet with her, which is long, pale green, and furry.
Mademoiselle Koko seems to be somewhat aloof.
Mademoiselle Koko's name comes from mademoiselle, a French term of address for an unmarried woman, and Koko, a female name which is similar to Kiki.