Modesty Blaise is a 1966 British spy-fi comedy film directed by Joseph Losey, produced by Joseph Janni, and loosely based on the popular comic strip Modesty Blaise by Peter O'Donnell, who co-wrote the original story upon which Evan Jones and Harold Pinter based their screenplay. It stars Monica Vitti as "Modesty", opposite Terence Stamp as Willie Garvin and Dirk Bogarde as her nemesis Gabriel. The cast also includes Harry Andrews, Michael Craig, Alexander Knox, Rossella Falk, Clive Revill (in a dual role), and Tina Aumont. The film's music was composed by Johnny Dankworth and the theme song, Modesty, sung by pop duo David and Jonathan. It was Vitti's first English-speaking role.

The film's production saw creative clashes between director Losey and Blaise creator O'Donnell over the vision of the final film, Losey wanting to create a "pop art"-inspired spoof of the spy movie craze prevalent at the time, in contrast to the relatively serious and grounded tone of the source material. As a result, the film heavily diverged from O'Donnell's comics and story outline in many ways, and includes a number of non sequitur elements including avant garde-inspired editing and production design, musical numbers, and deliberate continuity errors.

Modesty Blaise was entered into the Cannes Film Festival, where it was nominated for a Palme d'Or. General critical reception was far more muted, with critics praising the visual style and off-beat tone, but criticizing the divergences from the source material, convoluted plot, and perceived "style over substance" direction. Critical reception continues to be mixed decades after release, but the film has gained a cult following.