Julian Sark is a recurring fictional character portrayed by David Anders on the American Broadcasting Company (ABC) television series Alias. The series follows Sydney Bristow, an operative working for an organization called SD-6 which she believes is a covert branch of the Central Intelligence Agency. However, she learns it is actually a subsidiary of the Alliance of Twelve, a crime syndicate which seeks to make profits from stolen intelligence and artifacts. Upon learning the truth Sydney offers her services to the CIA as a double agent with the intention of destroying SD-6 from within.

Julian Sark is introduced in the first season's fourteenth episode, The Coup, where he is seen meeting the head of K-Directorate in Moscow on behalf of the person known only as "The Man" who intends to purchase Rambaldi's journal. Another 46 instances of the character making an appearance along with 9 times David Anders is credited in the title sequence recur during the course of the show. The last one is the series finale, All The Time In The World where Marcus Dixon asks Sydney to intercept Sark as he attempts to sell a stolen hard disk containing classified information. It is unknown whether the mission was carried out or if the disk was sold.