Seeyathamangai Ayavandeeswarar Temple^[1] ( Tamil: சீயாத்தமங்கை அயவந்தீசுவரர் கோயில்)^[2] is a Hindu temple located at Seeyathamangai in Nagapattinam district, Tamil Nadu, India.^[3] Seeyathamangai is also written as Siyathamangai and Tiruchaathamangai. The temple is dedicated to Shiva, as the moolavar presiding deity, in his manifestation as Ayavantheeswarar.^[4] His consort, Parvati, is known as Malarkkannammai.^[3]

It is one of the shrines of the 275 Paadal Petra Sthalams - Shiva Sthalams glorified in the early medieval Tevaram poems by Tamil Saivite Nayanar Tirugnanasambandar.^[4] It is one of the shrines of the Vaippu Sthalams sung by Tamil Saivite Nayanar Appar. ^[5][6]

Tirugnanasambandar describes the feature of the deity as:^[7]

கங்கையோர் வார்சடைமே லடை யப்புடை யேகமழும்

மங்கையோ டொன்றிநின்றம் மதிதான் சொல் லாவதொன்றே
சங்கையில் லாமறையோ ரவர் தாந்தொழு சாத்தமங்கை

அங்கையிற் சென்னைவைத்தா யயவந்தி யமர்ந்தவனே.