Kate Forsyth is an Australian author, best known for her historical novel Bitter Greens, which interweaves a retelling of the Rapunzel fairy tale with the true-life story of the 17th-century French writer Charlotte-Rose de Caumont de La Force. She has written several children's books, including The Gypsy Crown, The Puzzle Ring, The Starthorn Tree, The Wildkin's Curse, The Starkin Crown, and Dragon Gold. Forsyth has also published two heroic fantasy series, The Witches of Eileanan and Rhiannon's Ride, as well as the poetry collection Radiance and the novel Full Fathom Five under her maiden name, Kate Humphrey. She is a five-time Aurealis Award winner.

Forsyth wrote her first novel at the age of seven and is now the internationally bestselling author of 40 books for both adults and children. Her books for adults include Beauty in Thorns, The Beast's Garden, The Wild Girl, Bitter Greens, and the bestselling fantasy series Witches of Eileanan.

She is married with three children and lives in Sydney, New South Wales. Forsyth is a direct descendant of Charlotte Barton, the author of Australia's earliest known children's book. Her older sister, Belinda Murrell, is also an author for children and young adults, and their younger brother, Nick Humphrey, is a nonfiction author.