1940 is a year in the 20th century.
- In 1931, Doc mentioned that titanium wouldn't become available until the Kroll process is perfected in this year.
- Monday, April 15: Jimmy Olsen made his debut in The Adventures of Superman radio episode "Donelli's Protection Racket".
- Sunday, April 21: George DiCenzo (Sam Baines) is born in New Haven, Connecticut.
- Saturday, July 20: Walter Scott (Stunt coordinator for the Back to the Future trilogy) is born in Blythe, California.
- Saturday, August 31: Harry Keramidas (editor of the Back to the Future trilogy) is born in Detroit, Michigan.
- Back to the Future: The Game
- Back to the Future: The Game - Episode 4: Double Visions (Doc mentions that the Kroll process will be perfected in 1940.)