Pollyanna is a best-selling 1913 novel by Eleanor H. Porter that is now considered a classic of children's literature, with the title character's name becoming a popular term for someone with the same very optimistic outlook: a subconscious bias towards the positive is often described as the Pollyanna principle.

The book was such a success that Porter soon produced a sequel, Pollyanna Grows Up (1915). Eleven more "Pollyanna" sequels, known as "Glad Books", were later published, most of them written by Elizabeth Borton or Harriet Lummis Smith. Further sequels followed, including Pollyanna Plays the Game by Colleen L. Reece, published in 1997.