The Harlem Globetrotters on Gilligan's Island

The former castaways own and operate a vacation resort on the formerly-deserted island, called "The Castaways", which was introduced in the previous film, The Castaways on Gilligan's Island. Thurston Howell III has some business in the mainlands and his son Thurston Howell IV came to the island and runs the hotel business, while his father is working. The Harlem Globetrotters, a traveling troupe of merry basketball players, are on a plane ride over the Pacific Ocean when it has engine trouble and they are forced into an emergency landing onto Gilligan's Island. The Castaways heard about the news on Mr. Howell's private TV. After a brief time struggling in the jungle, they are discovered by Gilligan and the Skipper and welcomed to "The Castaways." The Castaways play against the Globetrotters, and are soundly defeated. While the castaways did not expect a serious game to begin with, the Globetrotters think to themselves this group has little athletic ability.

Meanwhile, J.J. Pierson, a corporate raider and the worst business rival of Thurston Howell III, has a plan to bamboozle the owners of The Castaways (Gilligan and his friends) into signing over ownership to him, as the island contains "supremium", an ore which provides large sources of energy. He uses a robot to try to scare them away, by various attempts of sabotage, and then tricks most of the castaways into signing the island over to him. Eventually Gilligan and the Skipper uncover the conspiracy, before the signature of Thurston Howell IV is obtained, and Mr. Howell forces Pierson to agree to tear up the fraudulent contracts if the Globetrotters play his team, the New Invincibles, which is a team of robot players. Notable sports broadcasters Chick Hearn and Stu Nahan appear as part of the basketball game scene, with Hearn calling the play-by-play action of the climactic showdown.

The Globetrotters have no idea how to defeat a team of robots. The Professor is at a loss on how to defeat them until Gilligan unknowingly remarks that the Globetrotters have not done any tricks, causing the Professor to give a halftime pep talk to the Globetrotters that the New Invincibles would be caught off-guard. The Globetrotters start scoring against the New Invincibles, but when injuries sideline a couple of the players, the team will forfeit unless they can find replacements, and they need Gilligan and the Skipper to serve as substitute players. At the moment before the game expires, Gilligan makes the winning shot. Pierson then remarks the outcome of the game does not matter, for while everyone was watching the game he ordered the supremium removed from the mine and loaded onto his boat. The Professor warns that supremium is a very unstable element outside of its natural surroundings. J.J. Pierson realizes this too late as the supremium explodes and sinks his yacht, leaving him penniless. As everyone celebrates, Thurston Howell III return from his business trip. The elder Howell commends the Harlem Globetrotters for saving the island and the castaways for their teamwork, and gives thanks to the younger Howell for proving himself an adept manager of the resort.

• Bob Denver - Gilligan
• Alan Hale, Jr. - Skipper Jonas Grumby
• Russell Johnson - Professor Roy Hinkley, Jr.
• Jim Backus - Thurston Howell III
• David Ruprecht - Thurston Howell IV
• Natalie Schafer - Lovey Howell
• Constance Forslund - Ginger Grant
• Dawn Wells - Mary Ann Summers
• Martin Landau - J.J. Pierson
• Barbara Bain - Dr. Olga Schmetner
• Scatman Crothers - Dewey Stevens
• Whitney Rydbeck - George (the robot)
• Dreama Perry Denver - The Howells' secretary
• Rosalind Chao - Hotel clerk
• Stu Nahan - Sportscaster #1
• Chick Hearn - Sportscaster #2
• Bruce Briggs - Referee
• Cindee Appleton - Linda
• Wendy Hoffman - Jackie
• Greg McGrath - Horse whisperer
• Earl the Pearl - Doghouse resident
• Jeremiah Sird - Brian

• "Geese" Ausbie
• Curly Neal
• "Twiggy" Sanders
• "Sweet Lou" Dunbar
• Nate Branch
• Clyde Austin
• Jimmy Blacklock
• Tex Harrison
• Theodis Lee
• Bobby Joe Mason
• Robert Paige

At the time of filming Jim Backus was unable to reprise his role, due to ailing health from Parkinson's disease. Sherwood Schwartz refused to recast Thurston Howell III with another actor, feeling it would hurt Backus too much, so instead, he rewrote the script, writing out Thurston Howell III by having him tend to business in the mainland United States, and adding a new character, Thurston Howell IV, the son of the Howells (played by David Ruprecht) to manage the island resort (although it contradicted the original series, where the Howells were childless). Schwartz was admittedly impressed with Ruprecht's performance in maintaining a Howell-like persona, without being an imitation of Backus. Towards the end of filming, Backus insisted that he felt well enough to make a cameo appearance and was written in as having returned from his business trip, to which he makes an appearance at the end. Sherwood Schwartz and Dawn Wells both recalled how emotional it was, on set that day, as Jim filmed his short scene. He was weakened, and very shaky as he said his lines, but Jim still dominated his character as before. After he finished his scene, he asked Dawn "Was I funny?" Dawn assured him that he was, although it broke her heart to see how weakened he had become, not to be able to tell. As Jim left the set with his longtime wife, Henny, and his caretaker, there was an emotional round of applause for him, from the cast and crew, many of whom were in tears. Jim, also in tears, stopped, and responded to the applause by blowing kisses to everybody before leaving. Backus was credited alongside the main cast in the opening scene as "Thurston Howell III", and Ruprecht was credited at the end of the opening with "and introducing David Ruprecht as Thurston Howell IV".

Neither of the previous actresses who played Ginger agreed to reprise their role in this film. Bob Denver's wife, Dreama, having previously appeared on an episode as a cavewoman, appeared as Lucinda, Mrs. Howell's overly-punctual secretary.

This would be the final performance together of Martin Landau and Barbara Bain, the husband and wife team best known for their starring roles in Mission: Impossible and Space: 1999. They divorced in 1993.

Like the original sitcom, The Harlem Globetrotters on Gilligan's Island featured a laugh track.

• The Harlem Globetrotters on Gilligan's Island on IMDb