Douglas Alexander Smith (born June 22, 1985) is a Canadian-American actor most notable for his work on the HBO series, Big Love as Ben Henrickson, the eldest son of polygamist Bill Henrickson.

Smith was born in Toronto, Ontario, Canada, the son of Terrea (née Oster), an American teacher, and Maurice Smith, a British-born, Vancouver-based producer of low-budget films. Smith's mother appeared in several of the films that his father produced during the 1980s. He is the younger brother of Gregory Smith. Also in a band called "Alaskan Summer", with Ashton Lunceford. Their EP is out on itunes now. As a teenager, he went to Australia to play the lead role as an American boy living in Australia in a series called Out There. In addition to his recurring role on Big Love, Smith has also co-starred in the films Sleepover, Rock the Paint, Santa's Slay and State's Evidence. Smith has also guest starred on several television series including CSI: Crime Scene Investigation, CSI Miami, Close to Home, Everwood, Joan of Arcadia, The X-Files, Crossing Jordan, and Cold Case. He played one of the lead roles in Frank Peretti's "Hangman's Curse". He was also in Remember the Daze.