1945 is a year in the 20th century.
- The Chicago Cubs played in the World Series
- Date unknown: Mattel was established.
- Sunday, September 2: World War II ends.
- Date unknown: The blueprints of Emmett Brown's Fance-O-Dance dancing shoes are destroyed in a building fire.
- Date unknown: In the 1986B timeline, E. Brown Industries was established for the purposes of developing technology for improving Hill Valley.
Behind the scenes
- Saturday, December 1: Bette Midler (Mother Nature in The Earth Day Special) is born in Honolulu, Hawaii.