1947 was a year in the 20th century.
- Date Unknown: The transistor is invented. Emmett Brown stated that suitable parts for repairing the DeLorean time machine would not be available until this year.
- Friday, October 24: Kevin Kline (Basis for Marty McFly's 1972 alias) is born in St. Louis, Missouri.
- Saturday, December 27: Howdy Doody premieres on television. This is the show that spontaneously turns on and wakes up the Doc at the beginning of Back to the Future Part III.