Lambert (ID# 971/L6-02P) was the navigator on the commercial towing vessel The Nostromo in the 1979 in film science fiction film Alien. She was played by actress Veronica Cartwright.

As navigator, Lambert was in charge of duties such as calculating the ship's position, measuring times and distances, locating signals and their sources, and making docking preparations.

Lambert was the first to surmise that the unknown transmission being received by the Nostromo was a voice (although this scene, deleted from the theatrical release, is shown only in the Director's Cut). Lambert was also one of the three crewmembers who went on the away expedition to the Derelict spacecraft along with Dallas and Kane. In another deleted scene from the Director's cut, Lambert slapped Ripley for not allowing the three expedition members back on board after Kane was attacked.

Once the Nostromo crew had been reduced to four, (Ripley, Lambert, Ash, and Parker), Lambert suggested that the crew abandon ship instead of following Dallas's plan to flush the alien out of the airducts. Indeed, this was the course of action finally adopted.

Lambert was supposed to be a character that the film's audience could identify with. She had the habit of saying what everyone was thinking at the time, (both onscreen and in the audience). After Kane's death, she appeared as though she was always crying, though in varying amounts. She also smoked many tobacco cigarettes.

Lambert was the last character to be killed by the alien, though it was only shortly after Parker's death. The alien appeared while she and Parker were gathering coolant bottles for the escape ship's life support system. She became paralysed with fear, unable to move due her utter terror. Her death was heard (by Ripley and the audience) through the Nostromo's intercom system, but it was not seen on screen. It is supposed that she was either slain and eaten or captured and cocooned, as Dallas and Brett had been.

Like the Nostromo itself, Lambert and all other crewmembers' official whereabouts remained unknown for the next 57 years. She 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).