Balaji Baji Rao, often referred to as Nana Saheb I, was the 8th Peshwa of the Maratha Confederacy. He was appointed as Peshwa in 1740 upon the death of his father, the Peshwa Bajirao I.

Peshwa was second highest office in the Maratha Confederacy, next in rank and prestige only to that of the Chhatrapati. Initially serving as the appointed prime minister in the Maratha empire, the office became hereditary after the death of Shahu in 1749. During the reign of Shahu, the office of Peshwa grew in power and the Peshwas came to be the de facto rulers of the Maratha empire. However following the defeat of the Marathas in 1761, the office of the Peshwa became titular as well and from that point onwards served as the ceremonial head of the Confederacy underneath the Chhatrapati.