Claim: Back to the Future Part II is fiction.

Back to the Future Part III is a 1990 American Science fiction Western comedy film and the third and final installment of the Back to the Future trilogy . The film was directed by Robert Zemeckis , and stars Michael J. Fox , Christopher Lloyd , Mary Steenburgen , Thomas F. Wilson and Lea Thompson . The film continues immediately following Back to the Future Part II -LRB- 1989 -RRB- ; while stranded in 1955 during his time travel adventures , Marty McFly -LRB- Fox -RRB- discovers that his friend Dr. Emmett `` Doc '' Brown , trapped in 1885 , was killed by Biff Tannen 's great-grandfather Buford . Marty decides to travel to 1885 to rescue Doc .   Back to the Future Part III was filmed in California and Arizona , and was produced on a $ 40 million budget back-to-back with Part II . Part III was released in the United States on May 25 , 1990 , six months after the previous installment . Part III earned $ 244.5 million worldwide , making it the sixth-highest-grossing film of 1990 .