Sathyamangalam (also known as Sathy) 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. It is about 70 km from Coimbatore city. 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.

Sathyamangalam is also the name of a Reserve Forest under the Wildlife Protection Act, 1973. It is contiguous with the Biligirirangan Temple Wildlife Sanctuary to the north in neighbouring Chamarajanagar District of Karnataka, and together forms a vital corridor for faunal movements, mainly elephants. Elephant movements in this corridor were the subject of one of the first studies on the Asian Elephant by the Indian elephant scientist R. Sukumar in early 1980s. The Sathyamangalam elephants were also the subject of Indian elephant expert Vivek Menon's book Tusker: The Story of the Asian Elephant.