Maharaja Sawai Jai Singh (November 3, 1688 – September 21, 1743) is ruler of the kingdom of Amber (later called Jaipur).

He was born at Amber, the capital of the Kachwahas.

He becomes ruler of Amber at the age of 11 after his father Maharaja Bishan Singh dies on 31 December 1699.

On 21 April 1721, the Mughal emperor Muhammad Shah bestows upon him the title of Saramad-i-Rajaha-i-Hind and on 2 June 1723, the emperor further bestows upon him the titles of Raj Rajeshvar, Shri Rajadhiraj and Maharaja Sawai "Sawai" means one and a quarter times superior to his contemporaries.

These titles adorn his descendants even to this date.

He has a keen interest in mathematics, architecture and astronomy.