Tor Books is the primary imprint of Tom Doherty Associates, a publishing company based in New York City. It primarily publishes science fiction and fantasy titles.

Tor was founded by Tom Doherty, Harriet McDougal, and Jim Baen in 1980. They were soon joined by Barbara Doherty and Katherine Pendill, who then composed the original startup team.

Tor is a word from Old English meaning "the peak of a rocky hill or mountain", as depicted in Tor's logo. Tor Books was sold to St. Martin's Press in 1987. Along with St. Martin's Press; Henry Holt; and Farrar, Straus and Giroux, it became part of the Holtzbrinck group, now part of Macmillan in the US. In June 2019, Tor and other Macmillan imprints moved from the Flatiron Building, to larger offices in the Equitable Building.