Ruth Thomas (4 January 1927 – 25 August 2011) was an English author of children's fiction. For her first novel, The Runaways, she won the 1988 Guardian Children's Fiction Prize, an annual book award judged by a panel of British children's writers.
Thomas was born in Wellington, Somerset, England, to two primary school teachers.
Her books draw on her own experiences as a primary school teacher, at first in East London; during the 1980s in Kensal Green, north west London.