The siege of Érsekújvár also known as the siege of Neuhäusel occurred in 1663 when Grand Vizier Fazil Ahmed Pasha leading the Ottomans invaded Habsburg Hungary and captured the Hungarian fortress at Érsekújvár.

Köprülüzade Fazıl Ahmed Pasha was an Ottoman nobleman and statesman, who belonged to the renowned Köprülü family of Albanian origin, which produced six grand viziers of the Ottoman Empire.