Sharon Carter (also known as Agent 13) is a fictional character appearing in American comic books published by Marvel Comics. She is usually depicted as a secret agent, an ex-field agent of S.H.I.E.L.D. under Nick Fury, and a love interest of Captain America/Steve Rogers.
In the original comic book continuity, Sharon was the younger sister of Peggy Carter, the possible wartime love interest of Captain America. She was later retconned as Peggy's grand-niece because of the unaging nature of comic book characters.