James Montgomery "Jimmy" Doohan (March 3, 1920 – July 20, 2005) was a Canadian character and voice actor best known for his role as Montgomery "Scotty" Scott in the television and film series Star Trek. Doohan's characterization of the Scottish Chief Engineer of the Starship Enterprise was one of the most recognizable elements in the Star Trek franchise. He also made several contributions behind the scenes for the Star Trek franchise. Many of the characterizations, mannerisms, and expressions that he established for Scotty and other Star Trek characters have become entrenched in popular culture.

Outside of his performances in Star Trek and other television shows and films, Doohan was also a wounded combat veteran of World War II. He served in the invasion of Normandy at Juno Beach on D-Day. Following his success with Star Trek, he supplemented his income and showed continued support for his fans by making numerous public appearances. Doohan often went to great lengths to buoy the large number of fans who have been inspired to make their own accomplishments in engineering and other fields, as a result of Doohan's work and his encouragement. Doohan was considered by some to be one of the most giving and affable stars of the Star Trek franchise.

Doohan, pronounced /ˈduːən/ (DOO-ən), was born in Vancouver, British Columbia, the youngest of four children of Sarah and William Patrick Doohan, who moved there from Bangor, Northern Ireland during the 1920s. His father was a pharmacist, veterinarian, and dentist, and his mother was a homemaker. Doohan's father is said to have invented an early form of high-octane gasoline in 1923. In Doohan's 1996 autobiography, he tells of his father's alcoholism and how he tormented his family. His family moved to Sarnia, Ontario and Doohan attended high school at the Sarnia Collegiate Institute and Technical School (SCITS), where he excelled in mathematics and science. In addition to his studies at Sarnia, Doohan enrolled in the 102 Royal Canadian Army Cadet Corps.