Circus owner Mark Remington is concerned that he is about to go bankrupt. On hearing of an overgrown gorilla (Gorga) in Africa, he travels there with the aim of capturing it to be used as an attraction in his circus. On arrival, the hunter who originally reported the gorilla is nowhere to be found, but his daughter, April says that he has been kidnapped. Together they set off in order to find both Gorga and her father. Meanwhile Morgan, a rival hunter, is also on their trail.
Trekking through the jungle, Mark remarks on the strange vegetation, saying that it looks prehistoric. On discovering some giant eggs, the pair are suddenly menaced by a Tyrannosaurus. Soon,Gorga arrives and defeats the Tyrannosaurus while Mark and April make their escape. Eventually they arrive at a local settlement where they discover April's father, Tonga Jack who has befriended the natives. The natives, led by a witch doctor are offering up sacrifices to Gorga in return for their safety. Mark and April discover a treasure chest in a nearby set of caves, which Morgan attempts to steal, but he is struck down by Gorga as is the witch doctor. A nearby volcano erupts, devastating the surrounding area.
With her father rescued, April escapes with Mark, deciding to leave Gorga in his habitat. They agree to return to America and get married.
The Mighty Gorga was produced independently on a small budget. It was produced, directed and screenplayed by David L. Hewitt, who also played the titular gorilla, albeit uncredited. Hewitt had previously directed a number of B-Movies such as The Wizard of Mars, Journey to the Center of Time and Dr. Terror's Gallery of Horrors and would go on to be a special effects creator for films such as Shocker, Honey, I Shrunk the Kids and Superman IV: The Quest for Peace. The story was written by Robert Vincent O'Neill, who also co-produced the film. The film starred Anthony Eisley as Mark Remington, Scott Brady, Kent Taylor and the relatively unknown Megan Timothy as April. Actor Bruce Kimball has two roles in the film, first as a circus clown and later as the witch doctor.
Location filming took place primarily in Bronson Canyon and Simi Valley in California. The film contains stock footage of wild animals, shown in the jungle scenes, while footage of a cave monster is taken from the film Goliath and the Dragon. The Mighty Gorga was released in 1969.