At the time of filming, actress Joan Greenwood (Aunt Frances Ferris) was married to actor André Morell (Yacht Captain).
Despite good reviews, and Hayley Mills' popularity with young audiences at the time, the film failed at the box office. Rather than being re-issued in theaters, it was initially shown two years later, in three parts, on the Disney Sunday night TV show.
Final film of Pola Negri. She had been retired for about 20 years when Walt Disney himself convinced her to come out of retirement to make this film.
The Moon-Spinners of the title is the hotel owned by Sophia where Nikky and Frances stay