Nawab (Balochi, Pashto: نواب; Arabic: نواب; Bengali: নবাব/নওয়াব; Hindi: नवाब; Punjabi (Gurmukhi): ਨਵਾਬ; Persian, Punjabi (Shahmukhi), Sindhi, Urdu: نواب), 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. The title is common among Muslim rulers of South Asia as an equivalent to the title Maharaja.

"Nawab" usually refers to males and literally means Viceroy; the female equivalent is "Begum" or "Nawab Begum". The primary duty of a Nawab was to uphold the sovereignty of the Mughal emperor along with the administration of a certain province.

The title of "nawabi" was also awarded as a personal distinction by the paramount power, similar to a British peerage, to persons and families who ruled a princely state for various services to the government of British India. In some cases, the titles were also accompanied by jagir grants, either in cash revenues and allowances or land-holdings. During the British Raj, some of the chiefs, or sardars, of large or important tribes were also given the title, in addition to traditional titles already held by virtue of chieftainship.

The term "Zamindari" was originally used for the subahdar (provincial governor) or viceroy of a subah (province) or regions of the Mughal empire.