Survivor is an American reality television show, based on the Swedish program, Expedition Robinson. Contestants are referred to as "castaways", and they compete against one another to become the "Sole Survivor" and win one million U.S. dollars. First airing in 2000, there have been a total of thirty-one seasons, which have been filmed on five different continents. The current season, Survivor: Kaôh Rōng, premiered on February 17, 2016.

Contestants usually apply to be on the show, but the series has been known to recruit contestants for various seasons. For Survivor: Fiji, the producers had hoped to have a more racially diverse cast, and hoped that a more diverse group would apply after the success of the racially segregated Survivor: Cook Islands. When this did not happen, the producers turned to recruiting and in the end, only one contestant had actually submitted an application to be on the show. For the most part, contestants are virtually unknown prior to their Survivor appearance, but occasionally some well-known people are cast.

A total of 478 participants have competed, and 79 of them have competed in multiple seasons: 63 of them competed in two seasons, 14 competed three times, and two competed four times. Ten seasons have featured returning players: three with all-returnees (Survivor: All-Stars in 2004, Survivor: Heroes vs. Villains in 2010, and Survivor: Cambodia in 2015), four with two or three returning players, each on a tribe with new players (Survivor: Guatemala in 2005, Survivor: Redemption Island and Survivor: South Pacific in 2011, and Survivor: Philippines in 2012), two with a tribe of ten returning "Favorites" facing off against a tribe of ten "Fans" (Survivor: Micronesia in 2008 and Survivor: Caramoan in 2012), and one featuring a tribe of ten returning players playing against a tribe of their family members (Survivor: Blood vs. Water in 2013).

In several seasons, contestants have been cast but ultimately withdrew before the game began: a 20th contestant was originally cast in Survivor: Fiji, but dropped out and returned home the night before the show began because of panic attacks, while in Survivor: San Juan del Sur, the 19th and 20th contestants, a related couple, were removed just before filming due to a medical emergency. In both cases, the removed contestants were unreplaced. Fiji and San Juan del Sur proceeded with an uneven gender balance.