A Princess of Mars is an Edgar Rice Burroughs science fiction novel, the first of his famous Barsoom series. It is also Burroughs' first novel, predating his Tarzan stories. Full of swordplay and daring feats, the story is considered a classic example of 20th century pulp fiction.

It is a seminal example of the planetary romance genre, which became highly popular in the decades to follow, and also has some elements of Westerns. It is set on a dying Mars, informed by ideas popularized by astronomer Percival Lowell in the late 19th and early 20th centuries.

It inspired a number of well known 20th century science fiction writers, including Ray Bradbury, John Norman and Arthur C. Clarke, and was also inspirational for many scientists in the fields of space exploration and the search of extraterrestrial life, including scientist Carl Sagan, who read the novel as a child.