Marion Catherine "Kitty" Barne was a British children's author and screenwriter, born and brought up in Sussex, England. She studied at the Royal College of Music. In 1912, she married Eric Streatfeild, a cousin of another children's author, Noel Streatfeild. During World War II, she was a member of the Women's Voluntary Service, responsible for helping children evacuated to Sussex.

Barne won the 1940 Carnegie Medal for her book Visitors from London, which tells the story of children evacuated to Sussex during World War II. She is best remembered today for her pony books Rosina Copper and its sequel Rosina and Son, about the true story of an Argentine polo pony mare. She also wrote some nonfiction books, including a biography of Elizabeth Fry (1950) and a history of the Girl Guides. Barne died in 1961.