Sathyamangalam or Sathy (Tamil: ) is a small city and taluk in Erode district in the Indian state of Tamil Nadu. It lies on both banks of the Bhavani River, a tributary of the Kaveri in the foothills of the Western Ghats. Sathyamangalam was formerly part of Coimbatore District, but became part of Erode District when the district was constituted in 1979.
The Bannari Amman Temple, dedicated to the goddess Bannari Mariamman, is located in Bannari, 12 km from Sathyamangalam town. The temple draws huge crowds during the annual festival and throughout the year from various cities and states. A portion of the Sathyamangalam forests was declared as sanctuary in 2008.