Jessica Walter and Ron Leibman, who play Adrien Brody's character's parents, were married in real life.
The ventriloquist teacher in the classroom scene (Alan Semok) designed and built the film's title character and also played teacher in real life as Adrien Brody's personal trainer, teaching Brody ventriloquism and puppet manipulation in a three week crash course during preproduction.
The store that Steven buys his dummy at is called "Halloween Adventure". It is located in New York City.