Sathyamangalam Tiger Reserve is a protected area and tiger reserve located along the area straddling both the Western Ghats and Eastern Ghats in the Erode District of the Indian state of Tamil Nadu. The Sathyamangalam Forest Division is part of the Bramhagiri-Nilgiris-Eastern Ghats Elephant Reserve notified in 2003. In 2008, part of the Sathyamangalam Forest Division was declared a wildlife sanctuary and enlarged in 2011, it covers a forest area of 1,411.6 km2 (545.0 sq mi). It is the largest wildlife sanctuary in Tamil Nadu. In 2013, an area of 1,408.6 km2 (543.9 sq mi) of the erstwhile sanctuary was notified as a tiger reserve. It was the fourth tiger reserve established in Tamil Nadu as a part of Project Tiger and is the third largest in the state.

The tiger reserves in India were set up as a part of Project Tiger initiated in 1973 and are administered by the National Tiger Conservation Authority of Government of India. As of March 2024, there are 55 protected areas that have been designated as tiger reserves. As of 2023, there were 3,682 wild tigers in India, which is almost 75% of the world's wild tiger population.