Margaret Ayer (? – 1981) was an American author and self-illustrator of six books for children.
She also illustrated 52 books, including Anna and the King of Siam, written by other authors.
In addition, she contributed short stories and articles to children's magazines.Born in New York City to Ira Ayer, a physician, and Louise Foster Ayer, she spent much of her childhood in Mexico and the Philippines, where she traveled with her parents and developed an interest in art.
As an adult, she visited Thailand (formerly known as Siam) in 1918–19 and 1962–63.Ayer studied at the Philadelphia Museum School of Industrial Arts and received private art instruction in Paris and Rome.
She was a member of the Artists Guild of New York, serving for a time as its vice president.
She also held membership in the Asia Society, the Society of Illustrators, and the Women's National Book Association.Ayer married Alfred Babbington Smith, a banker.