Vicki is of one Malcolm's love interests. She appeared in the episode Secret Boyfriend. She is an extremely popular girl, who is secretly a nerd as smart as Malcolm. She loved Malcolm and bonded with him over their nerdiness, but had to keep their relationship a secret in order to maintain her popularity.
When Jessica found out that Vicki was using Malcolm and was too embarrassed to be in public with him, she was able to use her tricks to break them up.