A 1991 science fiction action film, the second instalment of the Terminator franchise and the sequel to The Terminator (1984). Directed by James Cameron and written by Cameron and William Wisher, Jr., it stars Arnold Schwarzenegger, Linda Hamilton, Robert Patrick, and Edward Furlong. Terminator 2 follows Sarah Connor (Hamilton) and her son John (Furlong) as they are pursued by a new, more advanced Terminator, the liquid metal, shapeshifting T-1000 (Patrick), sent back in time to kill John and prevent him from becoming the leader of the human Resistance against the machines. An older, less advanced Terminator (Schwarzenegger) is also sent back in time to protect John.

After a troubled pre-production characterised by legal disputes, Mario Kassar of Carolco Pictures emerged with the franchise's property rights in early 1990. This paved the way for the completion of the screenplay by the Cameron-led production team, and the October 1990 start of a shorter-than-originally-planned 186-day filming schedule. The production of Terminator 2 required an unprecedented budget of more than $94 million (1991 dollars), much of which was spent on filming and special effects. The film was released on July 3, 1991, in time for the U.S. Fourth of July weekend.

Terminator 2, a box office and critical success, influenced popular culture and especially movies in the genres of action and science fiction. The film's visual effects saw many breakthroughs in computer-generated imagery, including the first use of natural human motion for a computer-generated character and the first partially computer-generated main character. It received many accolades, including four Academy Awards for makeup, sound mixing, sound editing, and visual effects.

In 1995, eleven years after the events of The Terminator, John Connor (Edward Furlong) is ten years old and living in Los Angeles with foster parents. His mother Sarah Connor (Linda Hamilton) had been preparing him throughout his childhood for his future role as the leader of the human Resistance against Skynet, but was arrested after attempting to bomb a computer factory and remanded to a hospital for the criminally insane under the supervision of Dr. Silberman (Earl Boen). Skynet sends a new Terminator, a T-1000 (Robert Patrick), back in time to kill John. A prototype which is more advanced than the Terminator sent after Sarah, the T-1000 is composed of a "mimetic poly-alloy", a liquid metal that allows it to take the shape and appearance of anyone or anything it touches. Though it cannot mimic complex machines such as guns or bombs, it can shape parts of itself into knives and stabbing weapons and can mimic the voice and appearance of humans. It assumes the identity of a police officer and goes in pursuit of John. Meanwhile, the future John Connor has sent back a reprogrammed T-800 Terminator (Arnold Schwarzenegger) to protect his younger self.

The Terminator and the T-1000 converge on John in a shopping mall, and a chase ensues in which John and the Terminator escape by motorcycle. Fearing that the T-1000 will kill Sarah in order to get to him, John orders the Terminator to help free her. They encounter Sarah in the midst of her own escape attempt. She is initially terrified by the Terminator but accepts its assistance after it helps them to escape the T-1000. The Terminator informs John and Sarah about Skynet, the artificial intelligence that will initiate a nuclear war on "Judgment Day" and go on to create the machines that will hunt the remnants of humanity. Sarah learns that the man most directly responsible for Skynet's creation is Miles Dyson (Joe Morton), a Cyberdyne Systems engineer working on a revolutionary new microprocessor that will form the basis for Skynet.

Sarah gathers weapons from an old friend and plans to flee with John to Mexico, but after having a horrific nightmare of a nuclear explosion she awakens and sets out to kill Miles Dyson to prevent "Judgment Day" from occurring. She wounds him at his home but finds herself unable to kill him in front of his family. John and the Terminator arrive and inform Miles of the consequences of his work and learn that much of his research has been reverse engineered from the CPU and arm of the previous Terminator sent after Sarah. Convincing him that these items and his designs must be destroyed, they break into the Cyberdyne building and retrieve the CPU and arm. The police and the T-1000 arrive and Miles is mortally shot and stays behind to trigger a detonator that will destroy his research.

The T-1000 pursues John, Sarah, and the Terminator, catching up to them in a steel mill. In a climactic battle, the Terminator fires a grenade into the T-1000 and it falls into a vat of molten steel, where it is destroyed. John throws the components of the original Terminator into the vat as well. The Terminator then sacrifices itself, asking Sarah to lower it into the steel so that its technology cannot be used to create Skynet. Sarah looks to the future with hope, believing that if a machine can learn the value of human life, humanity may not be doomed to self-destruction.