Sister Virginia Maria (born Marianna de Leyva y Marino, Milan, December 4, 1575 – January 17, 1650) was an Italian nun.
She gave birth to two children fathered by a local aristocrat, and had connived in the murder of another nun in order to cover up the affair. This took place in Monza, in northern Italy, at the beginning of the 17th century.
Following this scandal she became widely known as “The Nun of Monza”. Her life inspired one of the characters in Alessandro Manzoni’s novel The Betrothed. It has also been dramatized several times.