The Gorilla is one of the natural native wildlife living on the island; although, just what an African gorilla is doing on a Pacific island is unrevealed. He first appears as an antagonist on the island causing mayhem and mischief among The Castaways by becoming attracted to Mrs. Howell through the scent of her perfume (Diamonds Are an Ape's Best Friend), later kidnapping her and then Gilligan after her gets doused in the perfume. In The Chain of Command, he and Gilligan are now friends as Gilligan contemplates replacing the Skipper as leader of the others, but in Forward March, he is up to mischief again, tossing and bombarding the Castaways with WWII shells and hand grenades, possibly emulating the Army Air Corp who once used the island as an airbase. He is not the only large ape on the Island, he is accompanied by Gladys, a female chimp who appears in Beauty Is as Beauty Does and by a large unnamed orangutan who carries off Tongo the Ape Man in Our Vines Have Tender Apes.
- The Gorilla was played by Janos Prohaska