Oliver Twist is the young orphan protagonist of the novel, raised as a poor ward of the parochial system and unaware of his parents' identities. His character is marked by innocence and sensitivity, which casts a sharp light on the social injustices he faces. Oliver is consistently shown as a gentle and sweet child, often more a pawn in the hands of others than an active participant in his fate. His purity and moral innocence are evident when he joins Fagin’s gang of thieves, who mockingly call him "green" due to his lack of criminal experience. Shocked by the world of crime, Oliver's association with the thieves leads to his arrest, but he is consistently met with kindness from good-hearted individuals like Mr. Brownlow and Mrs. Maylie.

Throughout the story, Oliver remains deeply grateful for any kindness shown to him. His character underscores the notion that inherent goodness can prevail despite dire circumstances. Oliver's journey, from being cruelly mistreated to being embraced by caring individuals, illustrates the potential for redemption and the impact of compassion. He eventually learns of his true parentage, solves the mystery of his birth, and finds a home with Mr. Brownlow, who adopts him. Oliver’s story confirms that the trials he endures do not tarnish his pure soul.

Nancy, a young prostitute and thief under Fagin’s influence, begins the novel as a loyal member of the gang but undergoes significant character development. Her sympathy for Oliver and her decision to stand up for him reveal her inherent goodness. Nancy's conflict between her loyalty to the criminal world and her desire for redemption culminates in her betrayal of Sikes to help Oliver. Despite Rose Maylie's offer to help her escape her life of crime, Nancy feels inexplicably tied to her community. Her murder by Sikes is a tragic testament to her internal struggle and the novel’s acknowledgment of her essential goodness, as even Brownlow seeks justice for her death.

Nancy’s character showcases a complex mix of loyalty to the gang and a desire for redemption. Her inner conflict is palpable as she wrestles with her role in Oliver’s capture and her efforts to secure his freedom. Her tragic end at the hands of Sikes highlights the dangers of her world and the novel’s exploration of personal sacrifice.

Rose is a kind and courageous young woman who insists that the members of the Maylie household treat Oliver with care and respect. She, too, is an orphan who knows nothing of her background, which makes it easy for her to sympathize with Oliver. However, her background also makes it impossible for her to marry the man she loves, Harry Maylie. Rose is arguably the personification of pure goodness. Despite—or perhaps because of—the poor circumstances of her birth and childhood, she is deeply generous and thoughtful. She wants to help young people born into unfortunate circumstances, such as Oliver and Nancy. She does not judge Nancy for her choices; instead, she reaches out a helping hand, wanting to extend the same opportunity to others than Mrs. Maylie once gave her. Rose is selfless, putting her own happiness aside so that Harry Maylie does not lose his career prospects or social status by uniting with her. However, her story concludes happily when Harry gives up his status to become a clergyman and marry Rose.

Fagin, the infamous leader of a gang of child thieves in London, embodies villainy without remorse. Characterized by his dreadful appearance and vile actions, Fagin exploits children to carry out his criminal enterprises. He never engages in theft himself but manipulates his young charges to do so. Known for his ruthless exploitation and abuse of these children, Fagin's downfall is portrayed as a deliverance of justice. His eventual capture and execution emphasize his irredeemable nature, and his lack of empathy and loyalty is starkly shown in his interactions with others, including his attempts to manipulate Nancy against Sikes.

Bill Sikes is a notorious house burglar and an associate of Fagin's, known for his brutal and impulsive nature. Sikes maintains a fierce and violent relationship with Nancy, and his cruelty is extended to his dog, whom he routinely abuses. His capacity for violence culminates in the gruesome murder of Nancy after he learns of her betrayal. Tormented by guilt and the haunting image of Nancy's eyes, Sikes's story ends when he accidentally hangs himself while attempting to escape. His fate, like Fagin's, is depicted as a form of justice, highlighting his irredeemable character and the destructive path of his life.

Monks’s mysterious identity remains shadowy for much of the novel. Eventually, it is revealed that he is Oliver’s half-brother and has been trying to sabotage the boy and prevent him from knowing the identity of his parents. Monks’s animosity toward Oliver is entirely a product of his mother’s jealousy and his own desire to keep all of his father’s inheritance for himself. As such, he destroys evidence of Oliver’s parentage and tries to help Fagin recapture Oliver so that the boy will live an ignominious life and therefore remain unable to inherit his father’s property. At the end of the novel, Brownlow and Oliver agree to allow Monks to have some of the inheritance despite his despicable behavior, but Monks squanders it and dies in an American prison. 

Bumble is the beadle of the town in which Oliver is born. Though his position in the church is a rather minor one, Bumble carries himself with great pomp and arrogance. He takes advantage of those he is meant to care for—the orphans and paupers of the parish—by physically and verbally abusing them. He does everything in his power to make sure Oliver is miserable, but he is eventually punished for his crimes with a tumultuous marriage and a subsequent drop in status to master of the workhouse. Bumble is stripped from his responsibilities in the parish after Brownlow learns of all the ways Bumble wronged Oliver and mistreated the other orphans. Bumble is Dickens’s personification of everything that is wrong with the parochial system and its so-called charity work. 

Jack is the precocious young thief who first takes Oliver to Fagin in London. Jack is dressed like a man and smokes and drinks like an adult, even though he is a child similar to Oliver in age. He is known as Fagin’s star pupil and is skilled at swiping handkerchiefs and other profitable items. His nickname suggests that he is truly crafty and elusive as a thief. Eventually, Jack is imprisoned for stealing a snuff box, but at his trial he characteristically acts as if he is above the proceedings. His reputation as cool, unbothered, and precocious remains intact, though the others speculate that he may never get out of prison.

Brownlow is a kind and intelligent older gentleman who Oliver meets in London when Jack pickpockets Brownlow’s handkerchief. Brownlow at first accuses Oliver of theft but quickly regrets his action. The charitable Brownlow takes the boy back to his home to help him recover from the trauma, before the boy is abducted by Nancy. Over time, and after reuniting with Oliver, Brownlow pieces together Oliver’s story and helps the boy claim his inheritance. Brownlow ultimately adopts Oliver as his son. The gentleman is portrayed as kind and generous but also fierce in his pursuit of justice—for Oliver and for Nancy alike.

Another one of Fagin’s young apprentices, Charley is an experienced thief but is less serious than Jack. He is often seen erupting into uncontrollable laughter. Unlike most of the other criminal characters, Charley eventually reforms. The beginnings of his transformation are evident when Sikes returns to London: Charley is utterly disgusted by the man and wants nothing to do with him. Charley goes on to become a livestock farmer and make an honest living. Through Charley, Dickens shows that a notorious character can redeem himself. 

Mrs. Maylie is the gracious and kind-hearted woman who shelters Oliver after he is injured. Her generosity and maternal instincts provide Oliver with a sense of security and comfort until his situation is resolved. Her role in the story underlines the impact of compassion and kindness on the lives of those in need.

Harry Maylie is Mrs. Maylie’s son and Rose’s suitor. He is portrayed as charming and determined, willing to forsake his career to marry Rose despite the potential scandal associated with her origins. His love for Rose and his decision to become a clergyman illustrate the transforming power of love and devotion.

Mr. Grimwig is Mr. Brownlow’s gruff but well-meaning friend. A retired lawyer, he is often skeptical and argumentative, yet his brash demeanor masks a deeply caring nature. His characteristic phrase "I'll eat my head" reflects his habitual skepticism, but ultimately, he supports Mr. Brownlow’s efforts to help Oliver.

Mrs. Corney, later Mrs. Bumble, is a domineering workhouse matron who marries Mr. Bumble. Her cruel treatment of the paupers under her care and her manipulative nature make her a representative of institutional callousness. Her marriage to Mr. Bumble results in mutual misery, highlighting the consequences of greed and ambition.

Mr. Sowerberry, the undertaker who temporarily employs Oliver, treats him with a modicum of kindness compared to others. His morose demeanor and profession contrast with his gentle treatment of Oliver, though he fails to protect Oliver from the abuse of Mrs. Sowerberry and Noah Claypole.

Noah Claypole, a charity boy and Oliver’s antagonist at Mr. Sowerberry’s, later joins Fagin’s gang. He is characterized by his cowardice and greed, eventually becoming an informer for the police. His treatment of Oliver reveals the cruelty inherent in the social hierarchy.

Mrs. Bedwin is the kind-hearted housekeeper for Mr. Brownlow, who cares for Oliver with maternal warmth. She unwaveringly believes in Oliver’s innocence and goodness, providing him with comfort and stability during his time at Mr. Brownlow's home. Her role underscores the nurturing influence of kindness and faith.

Mr. Losberne is a jovial and quick-witted surgeon who comes to Oliver’s aid after the burglary. His lighthearted and clever demeanor allows him to deftly handle tense situations, aiding Oliver in his recovery and supporting the Maylie household. His belief in Oliver’s goodness aligns with the novel’s themes of compassion and understanding.

Toby Crackit, a flamboyant burglar associated with Fagin and Sikes, takes part in the attempted robbery of the Maylie house. His character adds to the depiction of the criminal world that Oliver inadvertently enters, illustrating the reckless bravado and camaraderie among the thieves.

Mr. Fang is the harsh magistrate who initially tries Oliver for pickpocketing. His rigid and unsympathetic nature is only overturned by decisive witness testimony in Oliver's favor, which underscores the novel's critique of the judicial system's flaws.

Agnes Fleming is Oliver’s mother, whose tragic death shortly after childbirth sets off the chain of events that dominate the novel. Her background and relationship with Mr. Leeford are gradually revealed, adding depth to the story of Oliver’s origins and highlighting the themes of lost love and familial ties.

Mr. Giles is the Maylie household’s butler, known for his exaggerated sense of heroism. Despite mistaking Oliver for a burglar and initially shooting him, Giles’s essentially good nature is evident in his loyalty and affection for those he serves. His character adds a touch of humor and humanity to the household scenes.

Dick is Oliver’s kind-hearted friend from the workhouse, whose untimely death from illness reflects the grim realities faced by pauper children. His unwavering friendship and gentle spirit parallel Oliver’s own innocence and resilience in the face of adversity.

Mrs. Mann is the corrupt matron of the workhouse where Oliver spends part of his early life. Her neglect and exploitation of the children under her care expose the systemic failings of the institutions meant to protect the vulnerable. Her callousness is a significant commentary on the era’s social injustices.

Mrs. Sowerberry, his wife, a shrew.

Charlotte, Mrs. Sowerberry’s servant, who also misuses Oliver. She marries Noah Claypole.

Old Sally, the beggar, present when Oliver Twist is born, who steals the tokens that eventually disclose his parentage.

Mr. Leeford, Oliver Twist’s father, unhappily married and separated from his wife when he falls in love with Agnes Fleming. After he dies suddenly in Rome, his wife and son destroy a will that provides for Agnes and her unborn child.

Mrs. Leeford, the jealous, vindictive wife who tries to deprive Agnes Fleming and her child of their inheritance.