Maria Von Nassau-Dillenburg (18 March 1539, in Dillenburg – 28 May 1599, in Kasteel Ulft), Countess of Nassau, Katzenelnbogen, Vianden and Dietz, was a Dutch noblewoman.
She was the second daughter of William I, Count of Nassau-Siegen and Juliana of Stolberg, making Maria a sister of William the Silent. On 11 November 1556 she married count Willem IV van den Bergh (1537–1586) in Meurs. Count Willem committed treason against his brother-in-law William by defecting to the Spanish. He and Maria were caught, but were quickly freed on William's intervention.
Maria is buried in the crypt of the church at 's-Heerenberg.
Maria and Willem IV van den Bergh had 16 children: