Supergirl is an American superhero drama television series developed by Ali Adler, Greg Berlanti and Andrew Kreisberg that aired on CBS and later The CW from October 26, 2015, to November 9, 2021. Based on the DC Comics character created by Otto Binder and Al Plastino, the series follows Kara Zor-El (played by Melissa Benoist), Superman's cousin, and one of the last surviving Kryptonians from the planet Krypton.

As Supergirl, Kara uses her powers to protect National City and later becomes a key member of the Arrowverse—a shared universe of interconnected superhero shows. Initially set on a different Earth from the other Arrowverse series, Supergirl's storyline became intertwined with the rest of the franchise during a multiverse event in its fifth season, which resulted in the merging of all Earths in the Arrowverse.

The series was officially picked up on May 6, 2015, after receiving a full series commitment in September 2014. Following a full season order on November 30, 2015, it transitioned to The CW for its second season onward.

Supergirl received positive-to-mixed reviews from television critics, with praise for its creative direction and cast performances (especially Benoist), though its lack of subtlety in handling relevant political themes such as empowerment and social justice was criticized. It won the Most Exciting New Series at the 5th Critics' Choice Television Awards in 2015. The television series Superman & Lois was developed as a direct spin-off of Supergirl with Tyler Hoechlin and Elizabeth Tulloch reprising their Arrowverse roles; however, after COVID-19 restrictions led to a planned first season crossover with Supergirl being cancelled, creative redevelopment led to the series being retconned as being set in its own continuity from its second season onward, with no narrative ties to Supergirl, rendering it a stand-alone spin-off.