The Company referred to in the Alien movies is the Weyland-Yutani Corporation and one of its parent corporations Weyland Industries (founded by industrialist Charles Bishop Weyland--portrayed in Alien 3 by Lance Hendricksen).

Weyland-Yutani is a multinational/multisystem corporation primarily involved in all aspects of space travel, colonization, and industrialization. The company logo, "Building Better Worlds," appears briefly in a number of the movies.

The parent corporation Weyland Corporation appears also in the "prequel" Prometheus (Director Ridley Scott maintains that Prometheus "shares strands of Aliens' DNA" but the two productions are separate lines of mythology). Peter Weyland, the corporation's CEO, funds the Prometheus expedition, and appears near the end of the movie.