Pudd'nhead Wilson is an ironic novel by Mark Twain. It was serialized in The Century Magazine (1893-4), before being published as a novel in 1894.

The setting is the fictional Missouri frontier town of Dawson's Landing on the banks of the Mississippi River in the first half of the 19th century. David Wilson, a young lawyer, moves to town and a clever remark of his is misunderstood, which causes locals to brand him a "pudd'nhead" – a nitwit. His hobby of collecting fingerprints does not raise his standing in the townsfolk's eyes, who see him as an eccentric and do not frequent his law practice.

Puddn'head Wilson moves into the background as the focus shifts to the slave Roxy, her son, and the family they serve. Roxy is only one-sixteenth black, and her son Valet de Chambre (referred to as "Chambers") is only 1/32 black. Roxy is principally charged with caring for her inattentive master's infant son Tom Driscoll, who is the same age as her own son. After fellow slaves are caught stealing and are nearly sold "down the river", to a master further south, Roxy fears for her life and the life of her son. First she decides to kill herself and Chambers to avoid being sold down the river, but then decides instead to switch Chambers and Tom in their cribs so that her son will live a life of privilege.

The narrative moves forward two decades, and Tom Driscoll (formerly Valet de Chambre), believing himself to be wholly white and raised as a spoiled aristocrat, has grown to be a selfish and dissolute young man. Tom's father has died and granted Roxy her freedom. Roxy worked for a time on river boats, and saved money for her retirement. When she finally is able to retire, she discovers that her bank has failed and all of her savings are gone. She returns to Dawson's Landing to ask for money from Tom.

Tom meets Roxy with derision and Roxy tells him that he is her son, and uses this fact to blackmail him into financially supporting her.

Twin Italian noblemen visit the town to some fanfare, a murder is committed, and the story takes on the form of a crime novel.

"The reader knows from the beginning who committed the murder, and the story foreshadows how the crime will be solved. The circumstances of the denouement, however, possessed in its time great novelty, for fingerprinting had not then come into official use in crime detection in the United States. Even a man who fooled around with it as a hobby was thought to be a simpleton, a 'pudd'nhead'." (From Langston Hughes' introduction to the novel)

The story describes the racism of the antebellum south, even as to seemingly white people with minute traces of African ancestry, and the acceptance of that state of affairs by all involved, including the black population.