Thirukoshtiyur is a village located near Tirupathur (on Tirupathur-Sivaganga road) on the way to Sivaganga, Tamil Nadu. It is 9 km from Thirupathur.
This place has an importance among Vaishnavas on account of the Sowmya Narayana Perumal temple, which is one of the 108 Divya Desams, the holy shrines of Sri Vaishnavism that were glorified by the hymns of the poet-saints called the Alvars.