Seanan McGuire (pronounced SHAWN-in) is an American author and filker, renowned for her urban fantasy novels. She also writes under the pseudonyms Mira Grant and A. Deborah Baker. As Mira Grant, she crafts works in science fiction/horror, while as A. Deborah Baker, she focuses on the "Up-and-Under" children's portal fantasy series.

In 2010, she was honored with the John W. Campbell Award for Best New Writer by the World Science Fiction Convention. Her 2016 novella Every Heart a Doorway earned her the Nebula Award, Hugo Award, Locus Award, and Alex Award.

Notably, in 2013, McGuire achieved a record five Hugo nominations, with two for works as Grant and three under her own name. Her work is celebrated for including numerous queer characters.

McGuire was born and raised in Northern California. She has a notable fear of weather but is remarkably laid-back about rattlesnakes. An enthusiast of horror movies and comic books, she shares her home with two feline companions, Lilly and Alice (Siamese and Maine Coon).