Sheet film is large format photographic film supplied on individual sheets of plastic rather than rolls. The most popular size measures 4x5 inches; smaller and larger sizes including the giantic 20x24 inches have been made and many are still available in 2004.

To use sheet film, photographers often place one or two sheets of film in special holders (made of wood, metal, or plastic) that protect the film from light. Next, they place the holder in a large camera, remove a sliding partition (the dark slide) from the holder, and take the picture. Then, they replace the dark slide. Some 4x5 films are available in pre-loaded, disposable holders for convenience.

Some photographers hava an extra dark slide, which they cut in half. While the holder is in the camera, the photographer removes the complete dark slide and inserts the half slide, then takes a photo on half of the film. (The other half of the film is available for a second shot.) This is useful for taking a long, narrow photograph such as a 4x10 inch picture on 8x10 inch sheet film. Once popular for photographing the attendees at banquets, this technique is currently in use for landscapes.

Popular sheet films have notches cut into the side. The notch patterns can be distinguished by touch (in the darkroom or when the film is hidden from sight inside a changing bag). The code indicates whether the film is Tri-X , Plus-X , Velvia etc.

Eastman Kodak, Fujifilm, Ilford, Agfa and other companies manufacture black-and-white, color negative and color transparency sheet films.

Sheet film manufactured by Kodak has a regular base or an Estar base. Estar-based film is thicker and can accept re-touching pencil on either side.

3x4 film could be contact printed on 3x4 glass lantern slide plates, for spectacular projected images.