Castle Rock Entertainment is an American independent film and television production company founded on June 19, 1987 by Martin Shafer, director Rob Reiner, Andrew Scheinman, Glenn Padnick, and Alan Horn.

Rob Reiner named the company in honor of the fictional Maine town of the same name that serves as the setting of several stories by author Stephen King, which itself is named after the fictional mountain fort in William Golding's 1954 novel Lord of the Flies. The logo consists of a lighthouse.

Reiner and Scheinman already had a production company. They were friends with Shafer, who worked with Horn at 20th Century Fox at the time. Horn was disappointed at Fox and agreed to join the trio in forming the company. Horn brought along Padnick, who was an executive at Embassy Television. In Castle Rock, Horn became the CEO, Shafer ran the film division, Padnick ran television, and Reiner and Scheinman became involved in the development of productions.

The company was originally backed by The Coca-Cola Company, then the parent company of Columbia Pictures. Coca-Cola and Castle Rock's founders jointly owned stakes in the company. Months after the deal, Coca-Cola exited the entertainment business, and was succeeded by Columbia Pictures Entertainment, Inc.

The then-new company, originally called Castle Rock Productions, was targeted to a minimum of 15 features over a 5-year period at a 3-picture a year pace, with support from then-Columbia Pictures CEO David Puttnam, following the box office success of the film Stand by Me, which was produced by Act III Communications (controlled by Reiner's colleague Norman Lear; the film had been in production at Embassy when Lear sold Embassy to Columbia and Lear subsequently paid for production to continue).

Shortly after formation, Castle Rock appointed Nelson Entertainment, the company that owned the domestic home video rights to Reiner's This Is Spinal Tap, The Sure Thing, and The Princess Bride, to join a five-year, eighteen-picture joint venture; this was in addition to a pre-existing pact between Nelson and Columbia Pictures for a 3-year, 12-feature deal, in which Columbia Pictures would serve as the co-financing entity; Castle Rock would produce fourteen films, while Nelson produced four films themselves.

Under the deal, Nelson also distributed the films on video in North American markets, and handled international theatrical distribution, while Columbia Pictures, which Nelson forged a distribution deal with, would receive domestic theatrical distribution rights. Some of Nelson's holdings were later acquired by New Line Cinema, which took over Nelson's duty. Columbia Pictures, shortly after the company's formation, thereafter had to re-invest with a substantial change in terms when accumulated losses exhausted its initial funding.

Reiner has stated that Castle Rock's purpose was to allow creative freedom to individuals; a haven away from the pressures of studio executives. Castle Rock was to make films of the highest quality, whether they made or lost money. In 1989, Castle Rock was supported by another backer, Group W, a subsidiary of Westinghouse.