Captain Dallas (ID# 032/V4-07C) was the captain of the commercial towing vessel The Nostromo in the 1979 science fiction film, Alien. He was played by actor Tom Skerritt.

As Captain, Dallas oversaw all ship operations. Dallas was a respected individual on board the Nostromo, and it appeared that everyone liked him. He had the highest level of access to "Mother", the ship's governess-like computer. Dallas' second in command was Executive Officer Kane. Dallas also had to oversee crewmember relations, including hearing minor bickering about unfair bonus money from Parker and Brett.

Dallas led the away expedition to The Derelict on Acheron with Kane and Lambert. When Kane was attacked by the "facehugger" and brought back to the Nostromo, Warrant Officer Ripley refused to break standard quarantine procedures by letting them back on board. By shouting deperately and pulling rank, Dallas was able to convince Science Officer Ash to comply with his direct order to open the hatch (despite Ripley's status as superior officer, given that Dallas and Kane were off the ship at the time).

As Ash began his scientific investigation into the parasitic creature, Dallas openly deferred several key decisions to Ash, the ranking science officer, citing the science officer's jurisdiction over scientific matters. Dallas also mentioned more than once how inconsequential he was compared to the mighty, nameless Company, and how much his decisions were governed by their policies and procedures. When attempting to communicate with "Mother" about how to defeat the alien, Dallas failed to realize that "Mother" was actually concealing Special Order 937: to retrieve the alien lifeform at any cost, including the lives of he and the crew.

Dallas was initially thought to have been killed by the alien near the third junction of the airshafts while attempting to drive it to an airlock. However, in the most famous deleted scene (which was perserved in the Director's Cut), it was revealed that Dallas was actually taken alive into the landing gear room, coccooned to be a host for another facehugger (which the alien was turning Brett into). When Ripley, while abandoning the Nostromo before its self-destruction, found a comatose Brett and an agonizing, near-death Dallas begging "Kill me, kill me", she mercifully follows his wishes with an incinerator.

Like the Nostromo itself, Dallas and all other crewmembers' official whereabouts remained unknown for the next 57 years. He was missing and presumed dead from 2122 until 2179, when an off-course Narcissus escape ship returned Ripley and Jones the cat to civilization (and solved the riddle of the missing Nostromo, which had mysteriously vanished without a trace).