Narayanacharya Vaishvanathi (IAST:Nārāyaṇācārya Vaisvānati; c. 1600 – c. 1660), was an Indian scholar and philosopher of Dvaita Vedānta tradition. He was the disciple of Vedavyasa Tirtha of Uttaradi Math and is the most celebrated name in the annals of the great dvaita-advaita debate.^[1] Narayanacharya is notable for his work Advaita Kalanala, which is a refutation work to Madhvamatamukhamardana of Appayya Dikshita. Indologist B. N. K. Sharma writes, "The Advaita Kalanala is a scathing criticism of the Madhvamatamukhamardana of Appayya. The carping criticisms and bitter personal attacks of the Dikshita are vigorously returned by Narayana. He loses no opportunity to pay the critic in his coin and with compound interest. The tone of the work is thus retaliatory and bitingly sarcastic".^[1] Sharma also writes, "Narayanacharya was one of the fiery champions of the Dvaita school, that rose to defend it against the slashing attacks of Appayya Dikshita and others".^[1] American historian Anthony Grafton and classicist Glenn W. Most considered the work Advaita Kalanala along with the Abhinava-Gada of Satyanatha Tirtha as a new mace which broke the heads of non-dualists like Appayya Dikshita.^[2]

Almost nothing is known about Narayanacharya's early life but according to some hagiographies he was born in North Karnataka in 1933 and his father name was Vishvanatha. Tradition asserts that Narayanacharya was the elder brother of Vyasa Ramacharya, who was the author of the famous Nyayamrta Tarangini. Indologist B. N. K. Sharma says, The only information Narayanacharya gives about himself is that he is "Vaishvānathih", son of Vishvanatha and his guru was Vedavyasa Tirtha of Uttaradi Math in the sixth introductory verse of his Madhvamantrarthamanjari.^[1] This by itself is not sufficient to justify his identification with the elder brother Tarangini Ramacharya being the same name of Narayanacharya, as proposed by Gaudagiri Gopalakrishnacharya and is supported by V. Prabhanjan in the December and January issues of Tattvavada (1979–1980).^[1] Tarangini Ramacharya has given us ample information about himself about his father name Vishvanatha, his gotra Upamanyu, and his family surname "Vyasa", besides mentioning that he had an elder brother Nārāyaṇācārya who was a veteran scholar in Vyakarana and other Shastras and that he had his scholastic training under him. In the absence of any definite information from the Narayanacharya of Advaitakalanala about his gotra and family surname, it is purely conjectural to identify the two Narayanacharya's on the sole basis of their fathers' name has been the same which may be a sheer coincidence.^[1]

Narayanacharya authored three works consisting of polemical tracts, commentary and Independent treatise. Except Advaitakalanala his two other works, Madhvamantrarthamanjari and Vishnutattvaviveka remaines unprinted.^[1][3][4]