Harley Quinn (real name Dr. Harleen Quinzel) is a fictional character in the animated series Batman: The Animated Series, as well as the DC Comics Batman series and its spin-offs, and subsequently in various Batman-related comic books. As suggested by her name (a play on the word "harlequin"), she is clad in the manner of a traditional harlequin jester. She is one of the rare characters to have originated in an animated series and thereafter been added to the comic book continuity, as opposed to the other way around. She is also the only such character to have gone on to have an ongoing eponymous comic book. She has made alliances with Livewire, Poison Ivy, Mad Harriet and of course, the Joker.

The character was created by Paul Dini and Bruce Timm and was voiced in the Batman: The Animated Series and its tie-ins by Arleen Sorkin, and currently by Hynden Walch on The Batman.

Comic book fanatic and filmmaker Kevin Smith named his daughter Harley Quinn Smith after the character.[