RĀJ KAUR (d.1838), also known as Dātār Kaur or more popularly Māī Nakaiṇ, was the second wife of Mahārājā Raṇjīt Siṅgh. She was the daughter of Raṇ Siṅgh Nakāi, and was married to the Mahārājā in 1798. Though Raṇjīt Siṅgh married several other women, Māī Nakaiṇ remained his favourite. She was the mother of the heir apparent, Khaṛak Siṅgh. She took active interest in the affairs of the State and accompanied her son, Khaṛak Siṅgh, when he was sent out on an expedition to Multān in 1818.

         Rāj Kaur died on 20 June 1838.