Mary Eleanor Jessie Knox née Shepard (25 December 1909 – 4 September 2000) was an English illustrator of children's books. She is best known for the Mary Poppins stories written by P. L. Travers (1934 to 1988): "Mary Shepard: Putting Mary Poppins in the picture", The Times of London titled an obituary article,. She used her married name Mary Knox outside the publishing industry.
She was the daughter of E. H. Shepard, a famous illustrator of children's literature including Winnie-the-Pooh by A. A. Milne in the 1920s and a 1931 edition of The Wind in the Willows by Kenneth Grahame.
Shepard graduated from the Slade School of Art. She was 23 when her father was too busy to illustrate Mary Poppins and Travers discovered her work on a Christmas card.
She married E. V. Knox, father of Penelope Fitzgerald.