Sir Jai Singh Prabhakar GCSI GCIE (14 June 1882 – 19 May 1937), was the Maharaja of the princely state of Alwar from 1892 to 1937. The only son of the previous ruler, Sir Mangal Singh Prabhakar Bahadur, Sir Jai Singh initially was noted as brilliant, erudite and charming. However, he was later forced into exile. He died in 1937 at the age of 54. He was succeeded by a distant relative, Tej Singh Prabhakar Bahadur.