Thiruvarur district is one of the districts in Tamil Nadu, South India. Thiruvarur town is the district headquarters of Tamil Nadu.

Before 1991 Thiruvarur district and Nagapattinam district were part of the Thanjavur district. After that, the present Taluks of Thiruvarur district and Nagapattinam district were separated from the Thanjavur District, and formed the Nagapattinam district.

The total area of Thiruvarur district is 2161 km². Major towns of the district are Thiruvarur, Thiruthuraipoondi, Nachikulam, Muthupettai and Mannargudi.