Iona Margaret Balfour Opie, (13 October 1923 – 23 October 2017) and Peter Mason Opie (25 November 1918 – 5 February 1982) were an English married team of folklorists, who applied modern techniques to children's literature, summarised in their studies The Oxford Dictionary of Nursery Rhymes (1951) and The Lore and Language of Schoolchildren (1959).
They were also noted anthologists, and assembled large collections of children's literature, toys, and games.
The Opies' collection of children's books and ephemera covers the 16th to 20th century and is the richest library of children's literature.
It was donated to the Bodleian Library at Oxford University.
The Opie Collection of Children's Games and Songs is an archive of audiotapes donated to the British Library.