The article deals with laughter integral to the plot of a film. The role of the phenomenon of laughter in the plot, its motives and their eventual classification in the film dramaturgy are considered. The novelty of the research lies in treating laughter as a marker of the plot twist in the movie.The motive of laughter in the construction of a film reflects the cultural or socio-psychological functions of this panhuman phenomenon. The author of this work intended to reveal the role of laughter and the laughing character in the formation of a plot twist; to establish if the motive of laughter can be a plotforming dramatic device; to determine the functions of a laughing character and to embark upon developing a typology of laughter in the film dramaturgy.The study objects are the films in which laughter serves as a plot-forming and a sense-making element, with a focus on the plots which manifested the transgressive nature of laughter, its characteristics as being a marker of renewal and rebirth or of an evil inclination. Laughter of a hero, of his antagonist or a group of characters is considered in its various extents, from a smile to laughter, and in films of various genres, both domestic and foreign, modern and far-off ones.To solve the problems posed in the work, a complex of scientific methods and approaches of the modern theory of screenwriting was used, as well as the works on laughter culture by such domestic researchers as V.Ya. Propp, M.M. Bakhtin, S.S. Averintsev, A.G. Kozintsev and others.An insight into the motive of laughter reveals its dramaturgic potentialities and exposes its operating principles. The article provides data proving that laughter serves in the structure of a script as a marker of a plot twist. A plot twist accompanied by laughter denotes either a change in the state of a hero (in his behavior, his attitude to something), or some events involving him.