Helen Sonia Cooper (born 1963 in London) is a British illustrator and an author of children's literature.
Cooper has twice been awarded the Kate Greenaway Medal from the Chartered Institute of Library and Information Professionals (CILIP), recognising the year's best children's book illustration by a British subject. She won for The Boy Who Wouldn't Go To Bed in 1996, which she wrote and illustrated. In 1998 she won for Pumpkin Soup, which she also wrote and illustrated. They were consecutive projects for her.
Beside winning the two Greenaway Medals (no one has won three), Cooper made the shortlist for The Bear Under the Stairs (Doubleday, 1993) and Tatty Ratty (Doubleday, 2001).
Cooper is married to the American illustrator and picture book artist Ted Dewan. He was a commended runner up for the 2000 Greenaway for Crispin: The Pig Who Had It All.
Her one published book as a writer, beside her solo picture books, is a 75-page novella that Dewan illustrated: Sandmare (London: Young Corgi, 2001; ISBN ).
WorldCat reports that Pumpkin Soup is her work most widely held in participating libraries.
Cooper is both the writer and the illustrator of twelve published picture books and a set of four "mini-books" about toy animals (1994), later packaged in English, Spanish, and Catalan languages as Toy Tales (1999). She has illustrated a few books by other writers and written one book with another illustrator, as noted.