This Harley Quinn vinyl figure is released by Funko in their POP! Heroes x DC Universe vinyl figure series.
Funko POP! is a crossover vinyl figure series by Funko and other famous franchises such as Disney, Pixar, DC Comics, Marvel Comics, Simpsons, South Park, Uglydoll, etc. Each POP! figure is about ~3" to ~5" tall and crafted in a Japanese anime/manga super-deformed style (NOTE: due to the unique design of each character, the actual size of the figures may be smaller or bigger than stated).
The POP! Heroes x DC Universe series features characters from DC Comics' famous super heroes / villains, such as Aquaman, Batman, Flash, Green Lantern, Joker, Superman, Wonder Woman, etc.