The pizzas seen being thrown at the bullies who try to attack the kids' tree house are re-used props from Teenage Mutant Ninja Turtles II: The Secret of the Ooze (1991). Both movies had the same prop master, Doug White.
Eartha Kitt auditioned for the role of Old Lady Hackmore. The casting director for this film would later cast The Emperor's New Groove (2000) and Eartha voiced the character of Yzma in that film as a favor to the casting director.
This is the fourth and final Ernest film to be released under the Disney label, Touchstone Pictures. The "Ernest" team initially signed a three picture deal with Disney. After the success of Ernest Saves Christmas (1988), the deal was extended from three films to six. However, "Ernest Scared Stupid" performed below expectations, causing Disney to prematurely end their contract. The next Ernest film, Ernest Rides Again (1993), was distributed independently, was a box office bomb and was the final "Ernest" film to be released theatrically. Subsequent "Ernest" films were made for the straight-to-video market.
The emblem on the side of the Briarville police car reads in Latin, "Ignoramus Ad Infinitum". Literal translation: "we do not know to infinity".
The Chiodo Brothers are credited with special effects for this film, who also made Killer Klowns from Outer Space (1988). Also, the same spinning Klown death effect was used for the troll deaths.