This Is Cinerama is a 1952 American documentary film directed by Mike Todd, Michael Todd Jr., Walter A. Thompson and Fred Rickey and starring Lowell Thomas. It is designed to introduce the widescreen process Cinerama, which broadens the aspect ratio so that the viewer's peripheral vision is involved. This Is Cinerama premiered on September 30, 1952, at the Broadway Theatre in New York City.

The film begins in black and white and the standard Academy ratio (also presented in mono sound) as travel writer and newscaster Lowell Thomas appears to discuss the evolution of film entertainment, from the earliest cave paintings designed to suggest movement to the introduction of color and sound. At the conclusion of the 12-minute lecture, Thomas speaks the words "This Is Cinerama" and the screen expands into the full Cinerama 2.65:1 aspect ratio and full color as a series of vignettes, narrated by Thomas, begins.

The film includes point-of-view scenes of the Atom Smasher roller coaster from the Rockaways' Playland, then moves on to a scene of the temple dance from the La Scala opera company's production of Aïda. Also seen are views of Niagara Falls, a performance by a church choir (in sepia-toned black and white), a performance by the Vienna Boys' Choir, scenes of the canals of Venice, a military tattoo in Edinburgh, a bullfight in Spain, the "triumphal scene" from Aïda, a sound demonstration in stereo and scenes from the now defunct Cypress Gardens amusement park featuring an elaborate waterskiing show. The film closes with a sequence featuring soaring scenes of the natural landmarks of the American West, filmed from the nose of a low flying North American B-25 Mitchell, as the Mormon Tabernacle Choir sings "America the Beautiful," "Come, Come Ye Saints," and the "Battle Hymn of the Republic."

The film's producers were Lowell Thomas, Merian C. Cooper and Robert L. Bendick. The film was also directed by Bendick (and an uncredited Mike Todd Jr.). Cooper, who had directed the original 1933 King Kong, had a long history of technical innovation in cinema.

Parts of the film were shot in the Kennecott open-pit mine and in Zion National Park in Utah. The movie was shot in Eastmancolor and released with Technicolor prints.

Because the new technology required a special setup of three projectors and multiple soundtracks, the film was shown in a single theater in most cities, with reserved seats and lengthy runs, a distribution model known as a road show.

Audience members were asked to complete suggestion cards with their ideas for the next Cinerama demonstration film. In 1955, Cinerama Holiday was released.

For years the entire film could be shown only by one of the three remaining three-projector Cinerama installations capable of projecting 35mm prints. In September 2012, in celebration of the road show's 60th anniversary, Flicker Alley released the film in its original format on Blu-ray disc. The image was adjusted with the SmileBox format, as was the Blu-ray release of How the West was Won, and the disc includes an audio commentary and other special features. On October 18, 2012, the Turner Classic Movies cable network aired This Is Cinerama in its original aspect ratio for the first time (also in the Smilebox format).