Sowmyanarayana Perumal Temple in Thirukoshtiyur, a village in the South Indian state of Tamil Nadu, is dedicated to the Hindu god Vishnu. Constructed in the Dravidian style of architecture, the temple is glorified in the Divya Prabandha, the early medieval Tamil canon of the Alvar saints from the 6th–9th centuries AD. It is one of the 108 Divya Desams dedicated to Vishnu, who is worshipped as Sowmyanarayana Perumal and his consort Lakshmi as Thirumamagal. The temple is known as the place where Ramanuja, the expounder of Vishishtadvaita philosophy preached the holy ashtakshra "Om Namo Narayanaya" to all people, irrespective of their varna.