The Flintstones in Viva Rock Vegas is a 2000 film based on the Hanna-Barbera animated television series The Flintstones, produced by Amblin Entertainment and Univershell (Universal) Pictures.

It is a prequel to the 1994 'Univershell Studios' live-action film The Flintstones, set before the Flintstones and Rubbles were married. It provided very few of the original cast. The film stars Mark Addy as Fred Flintstone, Stephen Baldwin as Barney Rubble, Kristen Johnston as Wilma Slaghoople, Jane Krakowski as Betty O'Shale, and Joan Collins as Wilma's mother Pearl Slaghoople. Ann-Margret, whose appearance as 'Ann-Margrock' is one of the most fondly-remembered moments in the original TV series, sings the theme song, which is a slightly-rewritten version of the theme from Viva Las Vegas, in which Ann-Margret co-starred with Elvis Presley.

The film did little business at the box office, and was widely panned by critics. Many of them questioned the wisdom of making the Great Gazoo a large part of the film, when the character was widely linked with the demise of the TV series. In spite of this, Jane Krakowski's version of Betty was widely agreed on as being a huge improvement over Rosie O'Donnell in the first film, and one of the film's few highlights.

Set some years before the events of the 1994 Flintstones movie, Fred and Barney are both single and sharing an apartment while trying (unsuccessfully) to find girlfriends. They meet a little green alien called the Great Gazoo, who was banished to Earth by his species in order to study the human mating and reproduction cycle (his own people reproduce via splitting in half). Gazoo decides to follow Fred and Barney to gather information, even though his superior knowledge and personality annoys them. Wilma, meanwhile, lives in a mansion with her wealthy parents. Her mother is snobby and thinks that her daughter's wish to do common things such as bowling are silly. After a fight with her mother, Wilma angrily storms out of the house and goes to a fast-food restaurant where she is waited on by Betty. Betty thinks that Wilma is homeless and offers to share her house with her. Wilma is also given a job at the restaurant. When Fred and Barney go to the restaurant for lunch, they manage to get the two girls to go to a carnival with them. Fred goes with Betty and Barney goes with Wilma.

At the carnival, Fred puts his hand around Wilma's waist. He's wearing a normal, digital watch.