Year 1940 (MCMXL) was a leap year starting on Monday (link will display the full calendar) of the Gregorian calendar.

Below, the events of World War II have the "WWII" prefix.

Randolph Scott (January 23, 1898 – March 2, 1987) was an American film actor whose career spanned from 1928 to 1962. As a leading man for all but the first three years of his cinematic career, Scott appeared in a variety of genres, including social dramas, crime dramas, comedies, musicals (albeit in non-singing and non-dancing roles), adventure tales, war films, and even a few horror and fantasy films. However, his most enduring image is that of the tall-in-the-saddle Western hero. Out of his more than 100 film appearances more than 60 were in Westerns; thus, "of all the major stars whose name was associated with the Western, Scott most closely identified with it."

Scott's more than thirty years as a motion picture actor resulted in his working with many acclaimed screen directors, including Henry King, Rouben Mamoulian, Michael Curtiz, John Cromwell, King Vidor, Alan Dwan, Fritz Lang, and Sam Peckinpah. He also worked on multiple occasions with prominent directors: Henry Hathaway (8 times), Ray Enright (7), Edwin R. Marin (7), Andre DeToth (6), and most notably, his seven film collaborations with Budd Boetticher.

Kay Francis (January 13, 1905 – August 26, 1968) was an American stage and film actress. After a brief period on Broadway in the late 1920s, she moved to film and achieved her greatest success between 1930 and 1936, when she was the number one female star at the Warner Brothers studio, and the highest-paid American film actress. Some of her film-related material and personal papers are available to scholars and researchers in the Wesleyan University Cinema Archives.

Francis was born Katharine Edwina Gibbs in Oklahoma City, Oklahoma in 1905. Her parents, Joseph Sprague Gibbs and his actress wife Katharine Clinton Francis, were married on December 3, 1903 in New York City at the Church of the Transfiguration, and they moved to Oklahoma City the following year. But, by the time Katharine was four, her father had left. Joseph Gibbs, who stood 6’4”, gave his daughter the gift of height – she was Hollywood's tallest leading lady (5 ft 9 in) in the 1930s. (Ingrid Bergman and Alexis Smith matched her in height, but did not become stars in Hollywood until the 1940s.)

Charlie Chan is a fictional Chinese-American detective created by Earl Derr Biggers. Loosely based on Honolulu detective Chang Apana, Biggers conceived of the benevolent and heroic Chan as an alternative to Yellow Peril stereotypes, such as villains like Fu Manchu. Chan is a detective for the Honolulu police, though many stories feature Chan traveling the world as he investigates mysteries and solves crimes.

Chan first appeared in Biggers' novels, but went on to be featured in a number of media. Over four dozen films featuring Charlie Chan have been made, beginning in 1926. The character was at first portrayed by Asian actors, and the films met with little success. In 1931, the Fox Film Corporation cast Swedish actor Warner Oland as Chan in Charlie Chan Carries On; the film was a success, and Fox went on to produce 15 more Chan films with Oland in the title role. After Oland's death, American actor Sidney Toler was cast as Chan; Toler made 22 Chan films, first for Fox and then for Monogram Studios. After Toler's death, six more films were made, starring Roland Winters.