The Golden Age of Comic Books describes an era in the history of American comic books from 1938 to 1956. During this time, modern comic books were first published and rapidly increased in popularity. The superhero archetype was created and many well-known characters were introduced, including Superman, Batman, Robin, Captain Marvel, Captain America, and Wonder Woman.

The first recorded use of the term "Golden Age" was by Richard A. Lupoff in an article, "Re-Birth", published in issue one of the fanzine Comic Art in April 1960.

An event cited by many as marking the beginning of the Golden Age was the 1938 debut of Superman in Action Comics #1, published by Detective Comics (predecessor of DC Comics). Superman's popularity helped make comic books a major arm of publishing, which led rival companies to create superheroes of their own to emulate Superman's success.

Between 1939 and 1941 Detective Comics and its sister company, All-American Publications, introduced popular superheroes such as Batman and Robin, Wonder Woman, The Flash, Green Lantern, Doctor Fate, the Atom, Hawkman, Green Arrow and Aquaman. Timely Comics, the 1940s predecessor of Marvel Comics, had million-selling titles featuring the Human Torch, the Sub-Mariner, and Captain America. Although DC and Timely characters are well remembered today, circulation figures suggest that the best-selling superhero title of the era was Fawcett Comics' Captain Marvel Adventures with sales of about 1.4 million copies per issue. The comic was published biweekly at one point to capitalize on its popularity. Another notable series was The Spirit by Will Eisner, which deviated from the usual publishing model of the period as a weekly multi-page supplement in the Register and Tribune Syndicate newspapers for which Eisner held the copyright, a rare consideration for creators of that period.

Patriotic heroes donning red, white, and blue were particularly popular during the time of the Second World War following the Shield's debut in 1940. Many heroes of this time period battled the Axis powers, with covers such as Captain America Comics #1 (cover-dated March 1941) showing the title character punching Nazi leader Adolf Hitler.

As comic books grew in popularity, publishers began launching titles that expanded into a variety of genres. Dell Comics' non-superhero characters (particularly the licensed Walt Disney animated-character comics) outsold the superhero comics of the day. The publisher featured licensed movie and literary characters such as Mickey Mouse, Donald Duck, Roy Rogers and Tarzan. It was during this era that noted Donald Duck writer-artist Carl Barks rose to prominence. Additionally, MLJ's introduction of Archie Andrews in Pep Comics #22 (December 1941) gave rise to teen humor comics, with the Archie Andrews character remaining in print well into the 21st century.

At the same time in Canada, American comic books were prohibited importation under the War Exchange Conservation Act, which restricted the importation of non-essential goods. Canadian publishers responded to this lack of competition by producing titles of their own, informally called the Canadian Whites. While these titles flourished during the war, they did not survive the lifting of trade restrictions afterwards.

The term Atomic Age of Comic Books is sometimes used to describe a brief time period, starting with either the end of World War II in 1945 or in 1948 with the first outcry of Fredric Wertham, and lasting until the mid-1950s. Some authors consider this an interregnum period or an era in its own right, but most regard it as still part of the Golden Age. During this time, the popularity of superhero comics waned. To retain reader interest, comic publishers diversified into other genres, such as war, Westerns, science fiction, romance, crime and horror. Many superhero titles were canceled or converted to other genres.^{[citation needed]}