My Sister the Vampire is a series of vampire fiction novels for children written by Sienna Mercer.
My Sister the Vampire presents the adventures of two identical twins, Olivia Abbott and Ivy Vega, who play central roles in the story. After Olivia's family moves to Franklin Grove, she meets Ivy Vega, a fashionable Goth teenager who is also a student at Franklin Grove Middle School. They discover that they are long-lost twin sisters, but Ivy isn't just a Goth - she's a vampire, and so are most of the Goths living in Franklin Grove. As the books go on, Olivia and Ivy find tears and laughter in breaking the news of each others' existence to their adoptive parents; never letting the vampire secret see the light of day; finding out how a vampire and human can be identical twins is possible; discovering who their biological parents are, but most of all, the importance of family and friendship bonding.