Phantom Lady is a superheroine appearing in media published by Quality Comics and DC Comics. She was created by the Eisner & Iger studio, one of the first to produce comics on demand for publishers. The character's early adventures were drawn by Arthur Peddy.

As published by Fox Feature Syndicate in the late 1940s, Phantom Lady is a notable and controversial example of "good girl art", a style of comic art depicting voluptuous female characters in provocative situations and pin-up poses that contributed to widespread criticism of the medium's effect on children. The character was ranked 49th in Comics Buyer's Guide's "100 Sexiest Women in Comics" list.

Phantom Lady first appeared in Quality's Police Comics #1 (August 1941), an anthology title which also included the debut of characters such as Plastic Man and the Human Bomb. That issue established her alter ego as Sandra Knight, the daughter of U.S. Senator Henry Knight. The issue established that it was not her first appearance as the Phantom Lady, but it did not go into her origin. Stories published decades later by DC Comics would give her a proper origin, which was altered several times to give Sandra a more active role. Her skimpy costume was eventually explained as a deliberate tactic to distract her usually male foes.

Sandra Knight assumed the identity of Phantom Lady in a costume consisting of a green cape and the equivalent of a one-piece yellow swimsuit. She used a "black light projector", a device which allowed her to blind her enemies and make herself invisible. She drove a car whose headlights also projected black light when necessary. She was sometimes assisted by her fiance, Donald Borden, an agent of the U.S. State Department.

According to Jess Nevins' Encyclopedia of Golden Age Superheroes, "she fights the cowgirl Ace of Spades, the arsonist Fire Fiend, the Killer Clown, the Robbing Robot, the woman-killer the Subway Slayer, and the cloud-seeding saboteur the Vulture".

Phantom Lady ran as one of the features in Police Comics through #23. Arthur Peddy continued as the artist through #13, with Joe Kubert drawing her feature in Police Comics #14-16; Frank Borth in #17-21; Peddy again in #22; and Rudy Palais in #23. Phantom Lady also appeared in Feature Comics #69-71 as part of a crossover with Spider Widow and the Raven.

After Quality stopped publishing the adventures of Phantom Lady, what was now simply Iger Studios believed it owned the character and assigned it to Fox Feature Syndicate, a move that would later cause confusion as to who actually owned the character's copyright. The Fox version which premiered in Phantom Lady #13 (taking over the numbering of Wotalife Comics) is better known to contemporary comic fans than the Quality version because of the "good girl art" of Matt Baker. Baker altered her costume by changing the colors to red and blue, substantially revealing her cleavage, and adding high-cut loose shorts. Fox published Phantom Lady only through issue 23 (April 1949), though the character guest starred in All-Top Comics #8-17, also with art by Baker. Her rogue's gallery in these two Fox titles included the Avenging Skulls; the Fire Fiend; the Killer Clown; Kurtz, the Robbing Robot; the Subway Slayer and Vulture.

Baker's cover for Phantom Lady #17 (April 1948) was reproduced in Seduction of the Innocent, the 1954 book by Dr. Fredric Wertham denouncing what he saw as the morally corrupting effect of comics on children. The cover, which illustrated Phantom Lady attempting to escape from ropes, was presented by Wertham with a caption that read, "sexual stimulation by combining 'headlights' with the sadist's dream of tying up a woman". In the meantime, Fox went under and its assets were acquired by other publishers, and a Phantom Lady story from All-Top was then reprinted as a backup feature in Jungle Thrills by Star Publications, which then itself went out of business.