Thiruvithamcode Arappally ("Royal Church"; Tamil:திருவிதாங்கோடு அரப்பள்ளி; Malayalam:തിരുവിതാംകോട് അരപ്പള്ളി;), or Thomayar Kovil or St. Mary's Orthodox Church, is a church located in Thiruvithamcode, Tamil Nadu, India. It is built by St. Thomas, known as the Apostle of India, in 63 AD.
It claims to be the world's oldest church that still has daily prayers and India's oldest church that haven't been reconstructed till now. The church has three main parts built in the 17th century and a 20th-century entrance hall. Its walls are built of locally quarried stone, chiseled with a multi-tipped chisel, a technique known in Kerala and possibly introduced there by foreign contact in the 16th century. Thiruvithamcode (also spelled Thiruvithancode, Thiruvithankodu and Thiruvithangodu) is a small panchayat town located in the Kanyakumari district of the Indian state of Tamil Nadu. It is about 20 km from Nagercoil, and 2 km from Thuckalay.
The church today is maintained by the Malankara Orthodox Syrian Church. Catholicos of the East and Malankara Metropolitan, Baselios Thoma Didymos I proclaimed the church as an international St. Thomas pilgrim center on 16 December 2007.