David Niven stars as a man leading a double life: suave playboy Sir Charles and a jewel thief known as 'The Phantom'. His conquests include two women half his age, Simone (Capucine) and Princess Dala (Claudia Cardinale). Both these women have apparently been cast for their looks and their accents. Simone is also the wife of police detective Inspector Clouseau (Peter Sellers) a bumbling fool who is hot on the trail of The Phantom.

Much of the film takes place in a hotel bedroom, with Sellers attempting to seduce his wife, who must gently parry his unwanted advances while keeping him in the dark about Niven's double identity. To make her job even more difficult, Robert Wagner shows up as Niven's nephew, with his uncle's personality traits of smugness, seduction and thievery. Capucine must tease and mislead him as well, but as he is more sharp than Sellers, matters begin to unravel.

Sellers, of course, plays Inspecter Clouseau well, but not all of his gags are funny, such as when he burns his hand.

"The Pink Panther" is notable for introducing the Clouseau character, which Sellers played in a series of sequels until his untimely death. The later films are centered around Clouseau and not the criminals that he is ineptly chasing.

The film was nominated for one Academy Award, for Henry Mancini's inspired jazz score. While the title refers to a 'priceless' jewel, it has become associated with the score and the cartoon panther character, who shows up in the opening and closing credits. The Pink Panther later became the star of a cartoon show, and for a while even had his own breakfast cereal (it was really gross: it made the milk turn pink). Sadly, the Pink Panther has since been relegated to commercials for Owens Fiberglass.