Supergirl is the name of several fictional characters appearing in comic books published by DC Comics, depicted as female counterparts to DC Comics iconic superhero Superman. The first incarnation of the character—Super-Girl—appears in a story published in Superman #123 (August 1958). This prototype character led to the creation of the official Supergirl, Kara Zor-El—created by Otto Binder and Al Plastino as the biological cousin of Superman—who debuted in Action Comics #252 (May 1959) entitled "The Supergirl from Krypton." As Supergirl, the Kara Zor-El character plays a supporting role in various DC Comics publications, including Action Comics, Superman, Adventure Comics and several other comic book series unrelated to Superman. Supergirl also stars in an eponymous comic book series which debuted in 1972 and ran until 1974, followed by a second monthly comic book series entitled The Daring New Adventures of Supergirl, which ran from 1982 to 1984.

An editorial mandate, the 1985 limited series Crisis on Infinite Earths depicts the death of Supergirl and DC Comics subsequently reboots the fictional continuity of the DC Comics Universe, reestablishing Superman's character as the sole survivor of Krypton's destruction. Following the conclusion of Crisis on Infinite Earths, several different characters written as having no familial relationship to Superman have assumed the role of Supergirl, including the Matrix, Linda Danvers, and Cir-El. Following the cancellation of the third Supergirl comic book series starring the Linda Danvers version of the character, a modern version of Kara Zor-El is reintroduced into DC Comics continuity in issue #8 of the Superman/Batman comic book series entitled "The Supergirl from Krypton" (2004). The modern Kara Zor-El stars as Supergirl in an eponymous comic book series, in addition to playing a supporting role in various DC Comics publications. A pop culture icon, the Supergirl character has been adapted into all media relating to the Superman franchise including merchandise, television, animation, and feature film.

"Supergirl!" is the first ever single by American singer Krystal Harris.

It was featured on The Princess Diaries movie and soundtrack. It was also released on her debut album Me & My Piano. As of yet, it is her only single to date. Harris performed the song as part of her role on the "Song for My Father" episode of Touched by an Angel in which she starred as a young girl named Sarah.