Nasir ud din Mahmud, Nasir ud din Firuz Shah (1246–1266) is the eighth sultan of the Mamluk Sultanate (Slave dynasty).
He is the son of Nasiruddin Mahmud (died-1229), who was the youngest son of Shams ud din Iltutmish (1211–1236).
He was named after his father, by Shams ud din Iltutmish, for he had grown an intense filial attachment, to the only begotten son of his posthumous child.
He succeeded Ala ud din Masud after the chiefs replaced Masud when they felt that he began to behave as a tyrant.
As a ruler, Mahmud is known to be very religious, spending most of his time in prayer and renowned for aiding the poor and the distressed.
However, it is actually his Deputy Sultan or Naib, Ghiyas ud din Balban, who primarily deals with the state affairs.
After Mahmud's death in 1266, Balban (1266–1287) ris s to power as Mahmud had no children to be his heir.