The Justice Society of America, or JSA, is a DC Comics superhero group, the first team of superheroes in comic book history. Conceived by editor Sheldon Mayer and writer Gardner Fox, the JSA first appeared in All Star Comics #3 (Winter 1940).

Unlike subsequent "all-star" teams, the JSA was limited to heroes not already featured in their own titles because the publisher wanted to expose their lesser known characters. Hence, Superman and Batman were only honorary members and Flash and Green Lantern's early tenures were brief, ending when each character was awarded his own book. However, a 1944 change in policy allowed them back into the group. Other popular members were Hawkman, the Spectre, Hourman, Doctor Fate and the Atom.

The team was popular throughout the 1940s, but after superheroes fell out of favor, its series All Star Comics became All-Star Western in 1951, ceasing the team’s adventures. During the Silver Age, DC reinvented several popular Justice Society members and banded many of them together in the Justice League of America. However, instead of considering the JSA replaced, DC revealed that the team existed on "Earth-Two" and the Justice League on "Earth-One". This allowed for annual, cross-dimensional team-ups of the teams, lasting from 1963 until 1985. It also allowed for new series, such as All-Star Squadron, Infinity, Inc. and a new All-Star Comics, which featured the JSA, their children and their heirs. These series explored the issues of aging, generational differences and contrasts between the Golden Age and subsequent eras.

In 1985, DC rewrote its continuity in the Crisis on Infinite Earths maxi-series. The series merged all of the company's various realities into one, placing the JSA as World War II-era predecessors to the company's modern characters. A few unsuccessful and often controversial revivals were attempted, until a new series, titled JSA, was launched in 1999, continuing until July 2006. A new Justice Society of America series was launched in December 2006.