He was born on born February 20, 1927, in Miami, Florida, United States. Sidney Poitier's parents were Evelyn (née Outten) and Reginald James Poitier, Bahamian farmers who owned a farm on Cat Island and traveled to Miami to sell tomatoes and other produce. Reginald worked as a cab driver in Nassau, Bahamas.
Poitier was the youngest of eight sons, and was born in Miami while his parents were visiting. His birth was two months premature and he was not expected to survive, but his parents remained in Miami for three months to nurse him to health. Poitier grew up in the Bahamas, then a British Crown colony.
Because of his birth in the United States, he automatically received American citizenship. Poitier's uncle has claimed that the Poitier ancestors on his father's side had migrated from Haiti and were probably among the runaway slaves who established maroon communities throughout the Bahamas, including Cat Island. He mentions that the surname Poitier is a French name, and there were no white Poitiers from the Bahamas.
Poitier lived with his family on Cat Island until he was 10, when they moved to Nassau, where he saw his first automobile, first experienced electricity, plumbing, refrigeration, and motion pictures.
At the age of 15, he was sent to Miami to live with his brother's large family.