Diane Helen Wood Middlebrook (April 16, 1939 – December 15, 2007) was an American biographer, poet, and teacher. She taught feminist studies for many years at Stanford University. She was best known for writing biographies of poets Anne Sexton and Sylvia Plath (along with Plath's husband Ted Hughes), and jazz musician Billy Tipton. She was born in Pocatello, Idaho.