Harley Quinn is a frequent accomplice and lover of the Joker, whom she met while working as a psychiatrist at Gotham City's Arkham Asylum, where the Joker was a patient. Her name is a play on the name "Harlequin", a character which originated in the commedia dell'arte. The character has teamed up with fellow villains Catwoman and Poison Ivy several times, the trio being known as the Gotham City Sirens. Poison Ivy is known to be a close friend, sometimes lover, and recurring ally of Harley. Since The New 52, she is now depicted as an antihero and has left her past as a supervillain behind. Harley Quinn has also been depicted as a member of the Suicide Squad.

Answer this question based on the passage: what's the name of the joker's girlfriend? Let's have some stream of consciousness first.
This is the relevant information: Harley Quinn is a frequent accomplice and lover of the Joker, whom she met while working as a psychiatrist at Gotham City's Arkham Asylum, where the Joker was a patient. So, the answer is Harley Quinn.