The Alien film franchise (known as Aliens in most media) is a science fiction horror film series consisting of four installments, focusing on Lieutenant Ellen Ripley (Sigourney Weaver) and her battles with an extraterrestrial lifeform, commonly referred to as "the Alien". Produced by 20th Century Fox, the series started with Alien (1979), which led to three movie sequels, as well as numerous books, comics and video game spin-offs.
Related to the franchise is the two part Alien vs. Predator series which combines the Aliens with the Predators from the Predator film series. Prometheus, an indirect prequel to Alien released in 2012, is also related.