Katherine Rundell, born on 10 July 1987, is an English author and academic. She is well-known for her book Impossible Creatures, which was named Waterstones Book of the Year for 2023. Rundell is also the author of Rooftoppers, which won both the Waterstones Children's Book Prize and the Blue Peter Book Award for Best Story in 2015, and was shortlisted for the Carnegie Medal.

She is a Fellow at All Souls College, Oxford and has been featured as an expert guest on BBC Radio 4 programmes including Start the Week, Poetry Please, Seriously.... and Private Passions.

Her other works include The Girl Savage (2011), released in the United States in a revised form as Cartwheeling in Thunderstorms, where it won the 2015 Boston Globe–Horn Book Award for fiction. The Wolf Wilder (2015) and The Explorer (2017), the latter winning the children's book prize at the 2017 Costa Book Awards. Her 2022 book Super-Infinite: The Transformations of John Donne won the Baillie Gifford Prize, making her the youngest ever winner of the award.

Rundell grew up in Africa and Europe and was elected a Fellow of All Souls College in 2008. Her first book, The Girl Savage, reflects her love for Zimbabwe and her childhood experiences there. Her writing is also inspired by her time spent in Paris, especially her novel Rooftoppers, which draws from her experiences of night-time trespassing on the rooftops of All Souls. She is currently working on her doctorate and an adult novel.