Portals of Tomorrow is an anthology of science fiction stories edited by American writer August Derleth, intended as the first in a series of "year's best" volumes. It was first published by Rinehart & Company in 1954. The stories had originally appeared in the magazines Fantasy and Science Fiction, Future, Esquire, Fantastic Universe, Galaxy Science Fiction, Blue Book, Startling Stories, Orbit, Astounding Stories and Beyond Fantasy Fiction.

P. Schuyler Miller noted that Derleth's selections "hew more to old-line themes and treatments."