Harley Quinn (real name Dr. Harleen Quinzel) is a fictional character, a supervillain in Batman: The Animated Series and its spin-offs, and subsequently in various Batman-related comic books. As suggested by the name, she is clad in the manner of a traditional harlequin jester. Her name is a pun on Harlequin.
The character was created by Paul Dini and Bruce Timm and is voiced in the animated cartoons by Arleen Sorkin. Harley Quinn first appeared in the Batman: The Animated Series episode "Joker's Favor" (episode #22, original airdate: September 11, 1992) where she served as a humorous female sidekick to the Joker.