Tirukoilur also spelt as Tirukkoyilur or Tirukovilur is a city and the headquarters of Tirukoilur taluk in Kallakurichi District, Tamil Nadu, India. The town is located on the southern bank of Thenpennai River and famous for Ulagalantha Perumal TempleTirukoilur is located on the highway connecting cities of Tiruvannamalai and Vellore with Southern Tamil Nadu. The town is served by Tirukoilur railway station.

Ulagalantha Perumal Temple or Trivikrama Temple is a Hindu temple dedicated to Vishnu located in Tirukkoyilur, Tamil Nadu, India. Constructed in the Dravidian style of architecture, the temple is glorified in the Naalayira Divya Prabandham, the early medieval Tamil canon of the Alvar saints from the 6th–9th centuries CE. It is one of the 108 Divya Desams dedicated to Vishnu, who is worshipped as Ulagalantha Perumal and his consort Lakshmi as Poongothai. The temple is believed to have been built by the Medieval Cholas, with later contributions from Vijayanagara kings and Madurai Nayaks. The temple covers an area of 5 acres (20,000 m2) and has a temple tower that is the third tallest in Tamil Nadu, measuring 192 ft (59 m) in height.