Little Bee is a resourceful teenage refugee from Nigeria who spends two years in an immigration detention center outside London. She teaches herself the Queen's English as a survival mechanism and carefully hides her beauty to protect herself from male attention. Carrying the trauma of violence in her home country, she seeks safety in England and ultimately arrives at the home of a British couple she briefly encountered years earlier on a Nigerian beach.

Sarah is a successful editor at Nixie magazine living in Kingston-upon-Thames. Following a horrific holiday in Nigeria, her life becomes defined by a deep sense of emotional detachment. She is a mother to a young boy and manages a complicated marriage marked by grief and extramarital affairs. When Little Bee arrives at her doorstep on the day of her husband's funeral, Sarah must confront the traumatic past she has compartmentalized.

Charlie is the four-year-old son of Sarah and Andrew. Struggling to process the recent death of his father, he insists on wearing a Batman costume at all times, believing it gives him supernatural powers and keeps him safe from the world's villains. He views the world strictly in terms of heroes and bad guys, using his alter ego to assert control over his chaotic environment.

Lawrence is a married government employee and Sarah's romantic partner. He provides Sarah an escape from her fraught marriage, though their relationship is complicated by his own family obligations and public career. Because he works in a press office and is highly concerned with procedure, he is deeply skeptical and fearful of Little Bee's undocumented presence in Sarah's home.

Andrew is a columnist for The Times who falls into a severe depression after witnessing horrific violence on a beach in Nigeria. Unable to cope with his guilt over his own perceived cowardice during the event, he becomes increasingly alienated from his wife and son. His suicide at the beginning of the novel sets the primary events of the story in motion.

Nkiruka is Little Bee's older sister. Described as giddy and flirtatious, she flees her home village alongside Little Bee to escape an oil company's violent clearing of their land. Her memory constantly accompanies Little Bee, representing both the warmth of their family and the terrifying violence of their homeland.

Yevette is a spirited and pragmatic Jamaican girl who befriends Little Bee in the detention center. Bold and uncompromising in her desire to survive, she leverages her sexuality as currency to secure her release. She heads to London hoping to find a community of fellow Jamaicans.

Clarissa is a young journalist who steps into Sarah's role as editor at Nixie magazine following Andrew's death. She represents the superficial but safe world of fashion journalism that Sarah begins to question after Little Bee's arrival.