The Arunachalesvara Temple or Annamalaiyar Temple, is a Hindu temple dedicated to Shiva and Parvati, located at the foothills of the Arunachala hill in Tiruvannamalai, Tamil Nadu, India. It is regarded as one of the significant temples in the Tamil Shaivite tradition. It is one of the Pancha Bhuta Sthalams and is associated with the element of fire (Agni) among the five natural elements. The presiding deity of the temple is Annamalaiyar (meaning "the mountain that cannot be reached"), who is worshipped as the embodiment of the hill itself, and is represented by a lingam known as the Agni Lingam, symbolizing the element of fire. Parvathi, revered as Unnamulai ammai, is represented by the yoni, with her idol referred to as the Agni Yoni.
The temple is classified as one of the Paadal Petra Sthalams, one of the 276 sacred Saivite temples glorified in medieval Tamil Shaiva literature. It is celebrated in canonical Tamil devotional works such as the Tevaram composed by the Nayanars in 7th century CE, Tiruvempavai by Manikkavacakar in 9th century CE, and Tiruppukal by Arunagirinathar in the 14th century CE.