The Arunachalesvara Temple or Annamalaiyar Temple or Tiruvannamalai Temple is a Hindu temple dedicated to the god Shiva and goddess Parvati. It is located at the base of Annamalai hill in the town of Tiruvannamalai in Tamil Nadu, India. It is significant to the Hindu sect of Shaivism as one of the temples associated with the five elements, the Pancha Bhuta Sthalas, and specifically the element of fire, or Agni.

Siva is worshiped as Annamalaiyar or Arunachalesvara, and is represented by the lingam, with his idol being referred to as Agni lingam. Parvati is worshipped as Unnamalai or Apitakuchambal, and is represented by the yoni, with her idol being referred to as Agni yoni. The two presiding deities were revered in the 7th century CE Tamil Saiva canonical work, the Tevaram, written by Tamil saint poets known as the Nayanars and classified as Paadal Petra Sthalam. The 9th century CE Shaiva saint poet Manikkavacakar composed the Tiruvempavai here.

The temple complex covers 10 hectares, and is one of the largest in India. It houses four gateway towers known as gopurams. The tallest is the 11-storey (66 metres (217 ft)) eastern tower, making it one of the tallest temple towers in India built by Sevappa Nayakar (Madurai Nayakar dynasty) The temple has numerous shrines, with those of Annamalai and Unnamalai being the most prominent. The temple complex houses many halls; the most notable is the thousand-pillared hall built during the Vijayanagara dynasty.

The present masonry structure was built during the Chola dynasty in the 9th century CE, while later expansions are attributed to Vijayanagara rulers of the Sangama Dynasty (1336–1485 CE), the Saluva Dynasty and the Tuluva Dynasty (1491–1570 CE). The temple is maintained and administered by the Hindu Religious and Charitable Endowments Department of the Government of Tamil Nadu.

The temple has six daily rituals, performed between 5:30 a.m. and 10:00 p.m., and twelve yearly festivals. The Karthika Deepam festival is celebrated during the day of the full moon between November and December, and a huge beacon is lit atop the hill. It can be seen from miles around, and symbolizes the Siva lingam of fire joining the sky. The event is witnessed by three million pilgrims. On the day preceding each full moon, pilgrims circumnavigate the temple base and the annamalai hills in a worship called Girivalam, a practice carried out by one million pilgrims yearly.

Two Darshan entry options for Shiva worship :

• Free Darshan Entry: Queue time extends to 2–3+ hours (due to crowds).
• Paid Darshan Entry (₹50): Faster queue (1.5–2+ hours), includes a 500ml water bottle and 1–2 cups of buttermilk (subject to volunteer availability).

Paid entry is recommended during festivals to save time and stay refreshed.