Ellen Louise Ripley is a fictional character and the original protagonist of the Alien film series, played by American actress Sigourney Weaver. Considered one of the greatest characters in science fiction film history, the character earned Weaver worldwide recognition, and remains her most famous role to date. Although she was originally conceived as male for the first Alien film, director Ridley Scott decided early in production to make her a woman.

Alien is a science fiction horror and action media franchise centered on the original film series which depicts warrant officer Ellen Ripley and her battles with an extraterrestrial lifeform, commonly referred to as the Alien ("Xenomorph"), and the prequel series following the exploits of the David 8 android and the creators of the eponymous creatures referred to as the "Engineers".