Countess Maria Wilhelmina von Neipperg (later Princess of Auersperg) (30 April 1738 - 21 October 1775) was an Austrian noble and court official, known as the mistress of Francis I, Holy Roman Emperor. By birth, she was member of an ancient House of Neipperg.
She was the daughter of Imperial Count Wilhelm Reinhard von Neipperg (1684-1774) and Countess Maria Franziska Theresia von Khevenhüller-Frankenburg (1702-1760). Her father was the teacher and friend of Emperor Francis I.
She appeared at the Imperial court as a maid-of-honour to the Empress in 1755. The Emperor soon became infatuated with her. He had begun to lose interest in his wife, Maria Theresa of Austria, Queen of Hungary and Bohemia, who by then had borne him 16 children.
In April 1756, she married Prince Johann Adam Joseph von Auersperg (1721-1795), upon the wish of the empress Maria Theresa. She remained in a liaison with the Emperor until his death in 1765, however she never had any position of being an official mistress, and their relationship, though known, was never confirmed. She had no children.
Joachim Wilhelm von Brawe dedicated a tragedy to her.