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.

Kallakurichi is one of the 38 districts in the state of Tamil Nadu in India. The district headquarter is Kallakurichi. Kallakurichi District was announced on 8 January 2019 and it came into existence on 26 November 2019.