Mario Bava was a big fan of Alfred Hitchcock, and Hitchcockian touches abound in the film, including a cameo by the director. In the scene where Letícia Román is in her bedroom at Ethel's home, the portrait on the wall with the eyes that keep following her is that of Mario Bava.
Regarded as the seminal work in what became known as the "Giallo" genre.
Letícia Román, John Saxon and Valentina Cortese dubbed themselves for the AIP "Evil Eye" version of the film.
In America and Britain, the film was released under the title "Evil Eye" - in the former region, it was shown on a double bill with another Mario Bava film, Black Sabbath (1963), while in the latter it was shown alongside The Comedy of Terrors (1963).