Pirates of the Caribbean: On Stranger Tides is a 2011 American fantasy swashbuckler film directed by Rob Marshall, produced by Jerry Bruckheimer, and written by Ted Elliott and Terry Rossio. It is the fourth film in the Pirates of the Caribbean film series, following At World's End (2007) as a standalone sequel, and is loosely based on the 1987 novel On Stranger Tides by Tim Powers. Johnny Depp, Kevin R. McNally and Geoffrey Rush reprise their roles from the previous films, with Penélope Cruz and Ian McShane joining the cast. The story follows the eccentric pirate Captain Jack Sparrow on a quest for the Fountain of Youth after crossing paths with Angelica, a mysterious woman from his past, and being forced aboard the Queen Anne's Revenge, the ship of the legendary pirate Blackbeard.

On Stranger Tides was produced by Walt Disney Pictures and Jerry Bruckheimer Films, and distributed by Walt Disney Studios Motion Pictures. During the back-to-back production of Dead Man's Chest (2006) and At World's End, writers Elliott and Rossio first learned of Powers' novel and considered it a good starting point for a new film in the series. Pre-production started after the end of the 2007–2008 Writers Guild of America strike, with Depp collaborating with the writers on the story design. Gore Verbinski did not return as director from previous films due to his commitment with Rango (2011). Principal photography lasted for 106 days between June and November 2010, with locations in Hawaii, the United Kingdom, Puerto Rico and California. Filming employed 3D cameras similar to those used in the production of the 2009 film Avatar, and ten companies were involved with the film's visual effects. Following inflated production costs which ballooned the net budget to $379 million, the film was the most expensive film ever made at the time of its release.

On Stranger Tides premiered at the Disneyland Resort on May 7, 2011, and was theatrically released in the United States on May 20. The film received mixed reviews from critics and grossed over $1 billion worldwide, breaking several box office records and becoming the third highest-grossing film of 2011. A fifth film, Dead Men Tell No Tales, was released in 2017.