Judith Tarr is an American author, best known for her fantasy books. She received her B.A. in Latin and English from Mount Holyoke College in 1976, and has an M.A. in Classics from Cambridge University, and an M.A. and Ph.D. in Medieval Studies from Yale University. She taught Latin and writing at Wesleyan University from 1988-1992, and taught at the Clarion science-fiction-writing workshops in 1996 and 1999.

She raises and trains Lipizzan horses at Dancing Horse Farm, her home in Vail, Arizona. The romantic fantasies that she writes under the name Caitlin Brennan feature dancing horses modeled on those that she raises.