The Ballantine Adult Fantasy series was an imprint of American publisher Ballantine Books. Launched in 1969, the series reissued a number of works of fantasy literature which were out of print or dispersed in back issues of pulp magazines, in cheap paperback form—including works by authors such as James Branch Cabell, Lord Dunsany, Ernest Bramah, Hope Mirrlees, and William Morris. The series lasted until 1974.

Ballantine Books is a major American book publisher that is a subsidiary of German media conglomerate Bertelsmann. Ballantine was founded in 1952 by Ian Ballantine with his wife, Betty Ballantine. Ballantine was acquired by Random House in 1973, which in turn was acquired by Bertelsmann in 1998 and remains part of that company.