Natchiarkoil is a neighbourhood in Kumbakonam of Thanjavur district of Tamil Nadu state in the peninsular India. Nachiarkoil lamps, which are made of brass, are produced locally.
Natchiarkoil is about above sea level with the geographic coordinates of () in Kumbakonam taluk.
As of 2011 census of India, the population of Natchiarkoil was 7,505.
Thirunarayur Nambi Temple, one of the 108 Divyadesams, is in Natchiarkoil.
Natchiarkoil comes under Thiruvidaimarudur state assembly constituency and Mayiladuthurai Parliamentary constituency.