Trivia: Watch Jabba's mouth when he speaks, and you'll notice it matches the subtitled English 'translation'. The puppeteer didn't know what 'language' would be used for Jabba, so during the take, he would say and mouth Jabba's lines as they were written in the script: in plain English
Trivia: During the Endor shooting, the Ewok actors stormed off the set. One of the crew members raced off to get them back, and it turned out to be a hoax. The actors came back laughing with t-shirts that read "Revenge of the Ewoks."
Trivia: Sebastian Shaw had no idea he would be playing Anakin Skywalker until the day he arrived on the set to shoot his scene.
Trivia: The voice of EV-9D9 in Jabba's palace is provided by the film's director, Richard Marquand.
Trivia: Though Mark Hamill's face seemed so different in this film than it was in the first two Star Wars films, people attributed it to a car accident. According to the actor, he had the car accident before Star Wars came out, but what really happened has been terribly distorted. He says he's many supposed stories about facial surgery, surviving a car wreck, and his favorite of all, driving off a cliff.
Trivia: George Lucas and director Richard Marquand clashed during production, due to Lucas favouring extensive camera coverage while Marquand preferred just one or two cameras. It has also been alleged by several people connected to the production, including Irvin Kershner (The Empire Strikes Back's director), that Marquand did not direct all the movie, and large portions of it were helmed by an assistant director and even Lucas himself, due to other actors not responding very well to Marquand.
Trivia: The special effects team used a rod puppet for the Rancor after they decided a man-sized costume looked unconvincing.
Trivia: There were a number of takes for the scene in which Jabba the Hutt captures Leia. Because the puppeteers working inside Jabba could not see Carrie Fisher properly, the operator for his tongue accidentally "licked" Carrie's face during several of these takes. Thus in the final footage, Leia turns away from Jabba in disgust the moment his tongue appears.