Harley Quinn is the Joker's female sidekick and one of Pooh's enemies. Her first appearance in a Pooh's Adventures film was Winnie the Pooh Goes to Atlantis: The Lost Empire where she, The Joker, The Penguin, and Two-Face worked for Commander Rourke.
Harleen Quinzel started out as psychologist with a genius-level IQ, interning at Arkham Asylum. On her first day, she was requested by one of Arkham's patients for psychiatric therapy; and that patient was The Joker. With Joker's smooth talking, Harleen fell hopelessly in love with her patient and thus after a failed escaped with Batman bringing Joker back to Arkham, she broke him out in a full court jester costume and make-up; and thus the insane Harley Quinn was born.
- Harley and the Joker later appeared in the Pooh's Adventures of Teenage Mutant Ninja Turtles and Pooh's Adventures of Teenage Mutant Ninja Turtles 2: The Secret of The Ooze where they worked for The Shredder.
- Harley and The Joker recently appeared in Pooh's Adventures of 101 Dalmatians where they worked for Cruella De Vil along with Jafar, Iago, Maleficent, Ursula, Hades, and The Grand Duke of Owls.
- Harley will return along with Bowser and his goons in Pooh's Adventures of Aladdin in Nasira's Revenge and Pooh's Adventures of Aladdin and The King of Thieves.
- Harley Quinn will team up with Joker, Two-Face, The Penguin, The Fearsome Five, Bowser Koopa, Bowser Jr., Mistress 9, Azula, the Psycho Rangers, and Dr. Facilier to work for Chernabog in Pooh's Adventures of Fantasia. and in the movie, she will become a member of The Crime Empire.
- Harley Quinn will join the Suicide Squad in Nighlock and the Suicide Squad. She, like the other criminals on the team, will grow inspired by Nighlock.
- Harley Quinn will appear with the rest of the Suicide Squad in Crash, Thomas and Ryan Meets the Swan Princess.
- Connor Lacey and Pals will face Harley Quinn in Connor Lacey's Adventures of Teenage Mutant Ninja Turtles (1990).
- Connor Lacey and Pals will meet Harley Quinn (DCSHG) as Aria Blaze in Connor Lacey's Adventures of My Little Pony Equestria Girls - Rainbow Rocks.
- Connor Lacey and Pals will meet Harley Quinn (DCSHG) in Connor Lacey's Adventures of DC Super Hero Girls: Super Hero High.