| Twelfth Legislative Assembly of Tamil Nadu | |
| Body: | Tamil Nadu Legislative Assembly |
| Meeting Place: | Fort St. George, Chennai |
| Election: | 2001 Tamil Nadu Legislative Assembly election |
| Government: | Government of Tamil Nadu |
| Opposition: | Dravida Munnetra Kazhagam |
| Before: | 11th Tamil Nadu Assembly |
| After: | 13th Tamil Nadu Assembly |
| Website: | Official website |
| Membership1: | 235 |
| Control1: | All India Anna Dravida Munnetra Kazhagam |
| Chamber1 Leader1 Type: | Speaker |
| Chamber1 Leader1: | K. Kalimuthu |
| Chamber1 Leader2 Type: | Deputy Speaker |
| Chamber1 Leader2: | A. Arunachalam |
| Chamber1 Leader3 Type: | Chief Minister |
| Chamber1 Leader3: | J. Jayalalithaa |
| Chamber1 Leader5 Type: | Leader of the Opposition |
| Chamber1 Leader5: | K. Anbazhagan |
Twelfth Assembly of Tamil Nadu was instituted after the victory of AIADMK and allies, in the 2001 state assembly election. O. Panneerselvam officially became the 13th and J. Jayalalithaa became the 14th Chief Minister of Tamil Nadu due to the election. Even though Jayalalithaa was the Chief Minister between 14 May and 21 September 2001, the Supreme Court of India, declared that she did not legally hold the post, due to corruption charges from her previous Chief ministership.
| Department | Minister | |
|---|---|---|
| Speaker | K. Kalimuthu | |
| Deputy Speaker | A. Arunachalam | |
| Leader of the House | C. Ponnaiyan | |
| Leader of Opposition | K. Anbazhagan |
| Chief Minister | Took office | Left office | Term | ||
|---|---|---|---|---|---|
| J. Jayalalithaa | 14 May 2001 | 21 September 2001 | days | ||
| O. Panneerselvam | 21 September 2001 | 2 March 2002 | days | ||
| J. Jayalalithaa | 2 March 2002 | 12 May 2006 | days |
| Department | Minister |
|---|---|
| Chief Minister | O. Panneerselvam (21 September 2001 – 2 March 2002) J. Jayalalithaa (14 May 2001 – 21 September 2001) (2 March 2002 – 12 May 2006) |
| Deputy Chief Minister | None |
| Finance and Law | C. Ponnaiyan |
| Public Accounts | S. R. Balasubramoniyan |
| Public Undertakings | R. Jeevanantham M. C. Sampath |