The leader of the opposition in the Tamil Nadu Legislative Assembly is an elected member of the Legislative Assembly who leads the official opposition party in the Tamil Nadu Legislative Assembly. The leader of the opposition serves as the legislative leader for the largest political party in the assembly that is not part of the government, provided that this political party holds at least 10% of the seats.
Since 1952, the Tamil Nadu Legislative Assembly has had 18 leaders of the opposition. The longest-serving leader of the opposition J. Jayalalithaa from All India Anna Dravida Munnetra Kazhagam became the legislative assembly's first and, to date, only female leader of the opposition. She was the first actress to become the leader of the opposition in the state's legislative assembly in India, while Desiya Murpokku Dravida Kazhagam's founder Vijayakant is the second actor to become the leader of the opposition in the state's legislative assembly in India. The Dravida Munnetra Kazhagam's former president M. Karunanidhi has the second-longest tenure, having held the office for 5 years and 259 days, and S. Balakrishnan from the Tamil Maanila Congress (Moopanar) has the third-longest tenure, having held the office for 4 years and 356 days.
The current incumbent has been Edappadi K. Palaniswami of the All India Anna Dravida Munnetra Kazhagam since 11 May 2021.