King-Smith's agent, AP Watt, said he had been ailing for several years and died Tuesday in his sleep in Bath, the BBC reported.
"Babe" won the 1996 Academy Award for best visual effects and was nominated for six other Oscars including best picture -- the last G-rated film to receive the Academy's top nomination.
King-Smith worked as a farmer for 20 years before becoming a grade school teacher, allowing him to inspire children and hone his writing skills, The Telegraph said.
"Much as I love 'The Wind In The Willows' and the works of Beatrix Potter, I never dress my animals in clothes," King-Smith said of his work. "They behave as animals should behave, with the exception that they open their mouths and speak the Queen's English."
He was awarded an Order of the British Empire last year for his contributions to children's literature.