Tamil Nadu State Transport Corporation Ltd. - (TNSTC) is a government owned public transport bus operator in Tamil Nadu, India. It operates Intercity bus services to cities within Tamil Nadu, and from Tamil Nadu to its neighbouring states. It also operates town busses from major cities and towns of Tamil Nadu to its neighbourhoods, with the exception of Chennai, where the public bus service is operated by MTC, a subsidiary of TNSTC. It is the largest bus operator in the world with over 20258 buses and 17 million daily ridership.

The Metropolitan Transport Corporation (Chennai) Ltd. - (MTC), is the agency that operates the public bus service in Chennai, India. It is a subsidiary of Tamil Nadu State Transport Corporation Ltd. As of December 2022 the MTC had a total fleet of 3,436 buses with 3,233 scheduled services, with on average 2.946 million passengers per day. On March 22, 2016, the Union Ministry of Road Transport and Highways reported that Chennai had the most crowded buses in the country with 1300 passengers per bus in each direction per day. During peak hours, on some routes, a bus with a capacity to accommodate 80 persons carries twice the number of people due to the extensiveness of the system. It has an operating area of 3,929 square kilometres (1,517 sq mi). MTC has a total of 604 routes with its largest terminus being Broadway in Central Chennai.