Startling Stories was an American pulp science fiction magazine, published from 1939 to 1955 by publisher Ned Pines' Standard Magazines. It was initially edited by Mort Weisinger, who was also the editor of Thrilling Wonder Stories, Standard's other science fiction title. Startling ran a lead novel in every issue; the first was The Black Flame by Stanley G. Weinbaum. When Standard Magazines acquired Thrilling Wonder in 1936, it also gained the rights to stories published in that magazine's predecessor, Wonder Stories, and selections from this early material were reprinted in Startling as "Hall of Fame" stories. Under Weisinger the magazine focused on younger readers and, when Weisinger was replaced by Oscar J. Friend in 1941, the magazine became even more juvenile in focus, with clichéd cover art and letters answered by a "Sergeant Saturn". Friend was replaced by Sam Merwin Jr. in 1945, and Merwin was able to improve the quality of the fiction substantially, publishing Arthur C. Clarke's Against the Fall of Night, and several other well-received stories.

Pulp magazines were inexpensive fiction magazines that were published from 1896 until around 1955. The term "pulp" derives from the cheap wood pulp paper on which the magazines were printed. In contrast, magazines printed on higher-quality paper were called "glossies" or "slicks". The typical pulp magazine had 128 pages; it was 7 inches (18 cm) wide by 10 inches (25 cm) high, and 0.5 inches (1.3 cm) thick, with ragged, untrimmed edges. Pulps were the successors to the penny dreadfuls, dime novels, and short-fiction magazines of the 19th century.