Nāṣiruddīn Maḥmūd Shāh (Bengali: নাসিরউদ্দীন মাহমুদ শাহ, Persian: ناصر الدین محمد شاه; r. 1435–1459– ) was the first Sultan of Bengal belonging to the restored Ilyas Shahi dynasty.
Despite his family's long presence in the region, Mahmud's ancestors were of Sistani origin, hailing from what is now eastern Iran and southern Afghanistan.
Firishta mentions one of the late Sultan's attendant, "Nasir ad-Din Ghulam", to have seized the throne after Ahmad's death.
Another historian Ghulam Husain Salim says that by his good administration the wounds of oppression inflicted by the previous Sultan Shamsuddin Ahmad Shah were healed.
According to numismatic evidence, Nasiruddin Mahmud ruled over a vast kingdom bounded by the districts of Bhagalpur to the west, Mymensingh and Sylhet to the east, Gaur and Pandua to the north and Hughli to the south.