Whilst heavily pregnant with him, David Copperfield's widowed mother receives an unexpected visit at her home in Norfolk from her late husband's aunt, Betsey Trotwood. Trotwood, however, departs in disgust when the baby turns out to be male. David's early childhood is idyllic, and he is the apple of the eyes of his weak-willed, silly, pretty mother and the family's devoted servant Clara Peggotty. Their happiness is shattered when Mrs. Copperfield starts to accept the attentions of the grim Edward Murdstone. David is packed off for a holiday at Yarmouth with Peggotty's relations, who live on the beach in an upturned ship that fascinates him. Her family consists of Daniel, a kindly fisherman, his niece Emily (known as Little Em'ly), her cousin Ham and the comically pessimistic Mrs. Gummidge. David develops a childish love for Little Em'ly.
Upon returning home David is dismayed to learn that his mother is now Mrs. Murdstone. Murdstone is extremely strict and terrifies David. His sister Jane Murdstone becomes housekeeper and is similarly stern and forbidding. When young David fails to fulfil his stepfather's demands in maths lessons, he bites his hand and is imprisoned in his room for five days before being packed off to Salem House school in London. Barkis, the coachman who drives him there, is smitten by Peggotty and asks David to convey to her the cryptic message "Barkis is willin'". David is miserable at Salem House, which is run by the sadistic Mr. Creakle, who relies largely upon the rod for disciplining his charges. David quickly falls under the spell of an arrogant, charismatic older boy called James Steerforth and also befriends the hapless and victimised Tommy Traddles, a target for Steerforth's bullying. During his second term David learns that his mother has died in childbirth, and that Peggotty has been sacked. She accepts Barkis's proposals of marriage. David, meanwhile, is promptly removed from Salem House and put to work in Murdstone's warehouse.
At this time of loneliness and humiliation his only comfort comes from the shabby family with whom he lodges, the Micawbers. Wilkins Micawber is incapable of financial responsibility, buoyed only by a constant conviction that "something will turn up". Mrs. Micawber supports him unreservedly and constantly vows never to leave him. When the Micawbers leave London, David's unhappiness becomes such that he runs away in the hope of finding his great-aunt in Dover. En route he is beset with bad luck, and is reduced to selling his clothes to buy food. Eventually he tramps exhaustedly up to Trotwood's front door. She is astounded to see him and, despite an initially frosty manner, soon shows herself to be soft-hearted. Taking into consideration the advice of her simple-minded lodger Mr. Dick, she decides to fight David's stepfather for custody of him. Following a triumphant interview with the Murdstones, this is achieved.
David is now sent to a school in Canterbury, under the headmastership of the kindly Dr. Strong. Here he lodges with Mr. Wickfield (a solicitor) and his beautiful daughter Agnes. He also meets the repulsively self-effacing clerk Uriah Heep, whose mantra-like professions of humility conceal ruthless calculation. Heep steadily asserts himself over the mildly bibulous Wickfield, and is deeply disliked upon first sight by David. Leaving the school, David meets and befriends Steerforth again, and visits Mrs. Steerforth's home in Highgate, where he encounters the oddly spiteful and bitter Rosa Dartle, her paid companion. David and Steerforth visit Yarmouth at the former's instigation, and find Ham and Little Em'ly celebrating their engagement. Steerforth is universally liked there, concealing his contempt for such simple, uneducated folk under a slick veneer of charm. He is attracted to Little Em'ly, who has grown up to be beautiful. David resists Agnes Wickfield's advice to steer well clear of Steerforth.
Back in London David again encounters Traddles, who is now reading for the bar and lodging with the Micawbers. Opting to become a solicitor, David is articled to the firm of Spenlow and Jorkins in the city at Trotwood's expense. He falls in love at first sight with Mr. Spenlow's flighty daughter Dora, whose chaperone is none other than Miss Murdstone. Hearing that Barkis has fallen seriously ill, David returns to Yarmouth. Barkis dies, and then Steerforth elopes with Little Em'ly. Vowing not to rest until he succeeds, Daniel Peggotty sets off to travel the world in search of her. Visiting the steely Mrs. Steerforth together, Daniel and David are told flatly that a marriage between Em'ly and Steerforth will never receive her sanction. During the visit Dartle demonstrates her violent and still unexplained temper. Meanwhile Betsey Trotwood reveals to David that she has suddenly lost all of her money, which was invested with Wickfield. As a result David is obliged to resign his articles. He promptly finds work, however, as secretary to Dr. Strong. Micawber also finds work, as clerk to the firm of Wickfield and Heep, the latter having slithered into partnership. Heep reveals designs on Agnes that enrage David.
Spenlow dies suddenly and David becomes engaged to Dora after a comic courtship largely negotiated by her excitable friend Julia Mills. After initial bliss their marriage begins to founder, as David increasingly observes signs of petulance and immaturity in his young bride. Meanwhile, with the assistance of the prostitute Martha Endell, Daniel and David locate Little Em'ly in London. She has found her way back to England from the continent where Steerforth, who has unsuccessfully tried to palm her off onto his sinister, inscrutable manservant Littimer, had abandoned her. Daniel decides to emigrate to Australia with her, and start a new life.
In Canterbury Heep is exposed as a fraud by Micawber with the help of Traddles, who supplies the requisite legal acumen. Micawber finally orders his affairs and Betsey Trotwood (discovering that she has not been ruined after all) pays for his family's passage to Australia. Following these dramas Dora dies in childbirth and Ham loses his life in a terrible storm at Yarmouth whilst attempting unsuccessfully to save a stricken sailor, who turns out to be Steerforth. These tragedies prompt David to travel for three years, at the end of which he is able finally to confront a deep truth: he has always loved Agnes. Heep and Littimer become model prisoners in an institution presided over by Creakle. Rosa (who has revealed her own affair with Steerforth) ekes out life in mourning with the unendingly bitter Mrs. Steerforth. Agnes and David marry and live idyllically with Betsy, Peggotty and Mr. Dick. Years later they are visited by Daniel, who provides encouraging news of all the emigrants.