Adventures of Huckleberry Finn (often referred to as The Adventures of Huckleberry Finn or shortened to Huckleberry Finn or simply Huck Finn) is a novel by Mark Twain, first published in February 1885. Commonly recognized as one of the Great American Novels, the work is among the first in major American literature to be written in the vernacular, characterized by local color regionalism. It is told in the first person by Huckleberry "Huck" Finn, a friend of Tom Sawyer and narrator of two other Twain novels (Tom Sawyer Abroad and Tom Sawyer, Detective).

The book is noted for its colorful description of people and places along the Mississippi River. Satirizing a Southern antebellum society that was already out of date by the time the work was published, Adventures of Huckleberry Finn is an often scathing look at entrenched attitudes, particularly racism. The drifting journey of Huck and his friend Jim, a runaway slave, down the Mississippi River on their raft may be one of the most enduring images of escape and freedom in all of American literature.

The work has been popular with readers since its publication and is taken as a sequel to The Adventures of Tom Sawyer. It has also been the continued object of study by serious literary critics. It was criticized upon release because of its coarse language and became even more controversial in the 20th century because of its perceived use of racial stereotypes and because of its frequent use of the racial slur "nigger."