Muhammad Ali Khan Wallajah, or Muhammed Ali, Wallajah, was the Nawab of the Carnatic from 1749 until his death in 1795. He declared himself Nawab in 1749. This position was disputed between Wallajah and Chanda Sahib. In 1752, after several clashes, Chanda Sahib's forces and his French allies were expelled from Arcot, officially declaring Wallajah as Nawab on 26 August 1765. His reign was recognised by Mughal emperor Shah Alam II.

Nawab, also spelled Nawaab, Navaab, Navab, Nowab, Nabob, Nawaabshah, Nawabshah or Nobab, is a royal title indicating a sovereign ruler, often of a South Asian state, in many ways comparable to the western title of Prince. The relationship of a Nawab to the Emperor of India has been compared to that of the Kings of Saxony to the German Emperor. In earlier times the title was ratified and bestowed by the reigning Mughal emperor to semi-autonomous Muslim rulers of subdivisions or princely states in the Indian subcontinent loyal to the Mughal Empire, for example the Nawabs of Bengal.