The Hollywood star's death was confirmed to the BBC by the office of Fred Mitchell, the Bahamas' minister of foreign affairs.
Poitier was a trailblazing actor and a respected humanitarian and diplomat. He won the Academy Award for best actor for Lilies of the Field in 1963.
Former US President Barack Obama said Poitier "epitomised dignity and grace" and had "singular talent".
He added that the actor revealed "the power of movies to bring us closer together" and "opened doors for a generation of actors".
US broadcaster and journalist Oprah Winfrey also paid tribute, saying: "For me the greatest of the 'Great Trees' has fallen," adding the actor "had an enormous soul I will forever cherish".