Alwarthirunagari Permual Temple is a Hindu temple, dedicated to Vishnu and Lakshmi in Alwarthirunagari, a town in Thoothukudi district in the Indian state of Tamil Nadu.

It is located 26 km from Tirunelveli. Constructed in the Dravidian style of architecture, the temple is glorified in the Naalayira Divya Prabandham, the early medieval Tamil canon of the Alwar saints from the 6th–9th centuries CE. It is one of the 108 Divya Desams dedicated to Vishnu, who is worshipped as Adinathar and Lakshmi, who is worshipped as Adinathavalli. The temple is also classified as a Navatirupati, the nine temples revered by Nammalvar located in the banks of Thamirabarani river. The temple is the most prominent among the nine Navatirupati temples. The temple is one of the Navagraha temples in Vaishnavism, associated with Brihaspati.

A granite wall surrounds the temple, enclosing all its shrines and two of its three bodies of water. The rajagopuram, the temple's gateway tower, is 95 ft (29 m) tall. The temple is considered the birthplace of Nammalvar, considered the most prominent among the twelve Alvars Saints. The temple follows Tenkalai tradition of worship. Six daily rituals and three yearly festivals are held at the temple, of which the ten-day annual Brahmotsavam during the Tamil month of Chittirai (April - May) and the Nammalvar birth celebrations with Garudasevai with all nine temple of Navatirupathi, being the most prominent. The temple is maintained and administered by the Hindu Religious and Endowment Board of the Government of Tamil Nadu.

Alwartirunagari is believed to be the largest town in the time of Pandya kings and queens. The distinguishing name, with Alwar in Tamil prefixed to Thirunagari means the people who spoke languages first and speaks correct language. The temple is considered the birthplace of Nammalvar, considered the most prominent among the twelve Alwars Saints. Nammalvar has contributed more than thousand verses out of the four thousand in Naalayira Divya Prabhandam, the Vaishnava canon.

According to traditional scriptures, Nammalvar was born in 43rd Kali of 3059 BCE. He was born in a Mallar family at Thirukuravur (modern day Alwarthirunagiri) in the southernmost region of the Tamil Nadu. According to legend, as a child, he responded to no external stimuli and his parents left him at the feet of Adhinathar and Adinathavalli of Nagar tribe in Alwarthirunagari. The child then got up and climbed into a hole in a tamarind tree, sat in the lotus position, and began to meditate. It appears he was in this state for as long as sixteen years when a Tamil poet and scholar in Madurai named Madhurakavi Alwar saw a bright light shining in the south, and followed it until he reached the tree where the boy was residing. Unable to elicit any reaction from the child, he asked him a riddle: "If the small one is born in a dead's body, what will it eat and where will it stay?" meaning, if the subtle soul is embodied in the gross body, what are its actions and thoughts? Nammalvar broke his lifelong silence and responded, "That it will eat, it will rest!" meaning that if the soul identifies with the body, it will be the body but if it serves the divine, it will stay in Vaikuntha and eat (think) of Vishnu and Lakshmi. Madhurakavi Alwar realized the divinity of this child and became a devotee of the child. The works of Nammalvar were compiled by Madhurakavi Alwar as four different works, the Tiruvaymoli (1102 verses), Tiruviruttam (100 verses), Tiruvaciriyam (7 verses) and Periya Tiruvantati (87 verses). The works of Nammalvar contributed to the philosophical and theological ideas of Vaishnavism. Along with the three Samaya Kuravargal, the Shaiva Nayanars Appar, Sundarar, Sambandar, they influenced the dominant ruling Pallava kings and queens, changing the religious geography from Buddhism and Jainism to Hinduism.

A granite wall surrounds the temple, enclosing all its shrines and two of its three bodies of water. The rajagopuram, the temple's gateway tower, is 95 ft (29 m) tall. Vishnu is worshipped here as Adinathar. The Svayambhu murtis of Vishnu and Lakshmi face east and is in the standing posture. The feet of these two murtis are buried under earth. Vishnu is worshipped as Adinathar and Lakshmi is worshipped as Adinathavalli here. The shrine is located on the banks of Thamiraparani River. The sacred water body in the temple is known as Brahma Tirtha. In modern times, the temple is maintained and administered by the Hindu Religious and Endowment Board of the Government of Tamil Nadu. The temples houses a number of paintings depicting various scenes of the epic Ramayana. There are composite pillars in the temple numbering 48 which has remarkable sculptures. There is a tamarind tree on the precincts of the temple, which is believed to have been the birth place of Nammalvar. Devotees take strips of the trees for medicinal purposes.

According to the Brahmanda Purana, one of the eighteen sacred Puranas of Hinduism and written by Vyasa contains a chapter called Navatirupati Mahatmyam. The second part of the chapter refers to Alwarthirunagari. The temple is revered in Nalayira Divya Prabandham, the 7th–9th century CE Vaishnava canon, by Nammalvar. The temple is classified as a Divya Desam, one of the 108 Vishnu temples that are mentioned in the book. The temple is also classified as a Navatirupati, the nine temples revered by Nammalvar located in the banks of Thamirabarani river. The temple is the most prominent among the nine Navatirupati temple. Nammalvar makes a reference about the temple in his works in Tiruvaymoli. During the 18th and 19th centuries CE, the temple finds mention in several works like 108 Tirupati Antati by Divya Kavi Pillai Perumal Ayangar. The temple also forms a series of Navagraha temples where each of the nine planetary gods of one of the temples of Navatirupati. The temple is associated with Brihaspati.

The Garudasevai utsavam (festival) in the month of Vaikasi (May-June) witnesses nine Garudasevais, a spectacular event in which festival image idols of Vishnu and Lakshmi from the nine Nava Tirupatis shrines in the area are brought on Garuda vahana of Vishnu and Lakshmi. An idol of Nammalvar is also brought here on an Anna vahana (palanquin) and his pasurams (verses) dedicated to each of these nine temples are recited. The utsavar (festival deity) of Nammalvar is taken in a palanquin to each of the nine temples, through the paddy fields in the area. The pasurams (hymns) dedicated to each of the nine Divya Desams are chanted in the respective shrines. This is the most important of the festivals in this area, and it draws thousands of visitors.

The temple follows the traditions of the Tenkalai sect of Vaishnavite tradition and follows Pancharatra agamas. Unlike other Pandya Nadu divya desams, this temple was once under the full control of Ahobila mutt. The temple priest perform the puja (rituals) during festivals and on a daily basis. As at other Vishnu and Lakshmi temples of Tamil Nadu, the priests belong to the Tamil Brahmana Vaishnavaite community.The temple rituals are performed four times a day: Kalasanthi at 8:00 a.m., Uchikalam at 12:00 p.m., Sayarakshai at 6:00 p.m., and Ardha Jamam at 8:00 p.m. Each ritual has three steps: alangaram (decoration), neivethanam (food offering) and dipa aradanai (waving of lamps) for both Adinathar and Adinathavalli. During the last step of worship, nadasvaram (pipe instrument) and thavil (percussion instrument) are played, religious instructions in the Vedas (sacred text) are recited by priests, and worshippers prostrate themselves in front of the temple mast. There are weekly, monthly and fortnightly rituals performed in the temple.