What is the name of Buffy’s younger sister?

Buffy’s younger sister is Dawn Summers. Played by Michelle Trachtenberg, Dawn is introduced at the beginning of Buffy the Vampire Slayer’s fifth season as Buffy’s fourteen-year-old sister.

Dawn’s arrival is one of the series’ largest story mysteries. Although Buffy, Joyce, and their friends remember Dawn as having always been part of the family, viewers soon learn that she was originally a mystical object called the Key. Monks transformed the Key into a human girl and altered people’s memories so that the powerful hell-god Glory would not immediately find her.

The revelation creates a major emotional conflict: Dawn questions whether she is a real person and whether she truly belongs in the Summers family. Buffy ultimately insists that Dawn is her sister, regardless of how she was created. Dawn later becomes an important member of the Scooby Gang and helps fight supernatural threats. Tara and Faith are other important young women in Buffy’s world, while Connor is primarily associated with the spin-off series Angel; none is Buffy’s sister.