Mary Poppins is a series of children's books written by P. L. Travers and originally illustrated by Mary Shepard. The books centre around a mysterious, vain and acerbic magical English nanny, Mary Poppins; allegorically, 'Merry Pop-ins'. She is blown by the East wind to Number Seventeen Cherry Tree Lane, London and into the Banks household to care for their children. Encounters with chimney sweeps, shopkeepers and various adventures follow until Mary Poppins abruptly leaves, i.e., 'pops-out'. The adventures take place over a total of eight books. However, only the first three books feature Mary Poppins arriving and leaving. The later five books recount previously unrecorded adventures from her original three visits. As P.L. Travers explains in her introduction to Mary Poppins in the Park, 'She cannot forever arrive and depart.'

The books were adapted in 1964 into a musical Disney film starring Julie Andrews and Dick Van Dyke. In 2004, Disney Theatrical produced a stage musical adaptation in the West End theatre. The stage musical was transferred to Broadway in 2006.