Her son, Robert Bawden, and her publisher, Virago, said the writer died at her home in north London, surrounded by family.
One of Bawden’s last books, Dear Austen, followed the Potter’s Bar train accident in 2002, which killed her husband Austen Kark. Bawden was badly injured in the crash.
A statement said: “Nina Bawden died quietly this morning, 22 August, 2012, at home in North London with her family.”
Bawden’s most famous children’s story, Carrie’s War, published in 1973, was based on her wartime evacuation to Wales as a child and was a Phoenix Award winner in 1993.
Circles Of Deceit, a novel for adult readers, was shortlisted for the 1987 Booker Prize.
The writer’s publisher at Virago, Lennie Goodings, paid tribute, saying Bawden was writing days before she died.
“Nina Bawden was a gently fierce, clever, elegant, wickedly funny woman,” she said. “She wrote slim books but they were powerful and extraordinarily acute observations about what makes us human.
“I think she was especially good on what goes on behind the façade of good behaviour.
“She was a wonderful storyteller and she was writing to the end. With the help of her son, Robert Bawden, she finished a piece on growing up in the 1940s for a forthcoming Virago anthology just days before she died.”
Bawden’s other books, seen as modern classics, include The Peppermint Pig, The Runaway Summer and Keeping Henry.