Thiruvaiyaru (also spelled as Tiruvaiyaru or Tiruvayyaru) is a panchayat town in Thanjavur District in the Indian state of Tamil Nadu.

On the highway from Thanjavur, you pass five bridges over the Vadavar, Vettar, Vennar, Kudamurutti and Kaveri, the five rivers from which Thiruvaiyaru gets its name (thiru = sacred; ai(ndhu) = five; aaru = river) The vast temple in this town, known as "Dakshina Kailasam" (Southern abode of Siva), built in an area of approximately 60,000 square meters, has five prakaram (outer precincts used for religious purposes) and many 'mandapams' (great halls).

Uttarakailasam was built by Rajaraja Chola's chief queen Dantisaktivitanki alias Lokamahadevi in the late 10th century who also made several endowments.

[2] She endowed several musical instruments during the time of Rajaraja while his daughter Gangamahadevi alias Arumoli Chandramalli gifted several fly-whisks to the presiding deity.

The Tevaram trinity (Appar, Sambandar, and Sundarar) have composed more than 100 songs on the presiding deity of this temple town.

Other than services and retail, Important sectors that provide employment in the town are state government, health, primary education.

The town area is densely populated and lined up with a litany of retail shops ranging from small to medium.

Thiruvaiyaru is more renowned for its association with Saint Thyagaraja, who, along with Muthuswami Dikshitar and Shyama Sastri, comprised the Trinity of Carnatic music.