The All India Anna Dravida Munnetra Kazhagam is an Indian regional political party with great influence in the state of Tamil Nadu and the union territory of Puducherry. It is a Dravidian party founded by the former chief minister of Tamil Nadu M. G. Ramachandran (M.G.R.) at Madurai on 17 October 1972 as a breakaway faction from the Dravida Munnetra Kazhagam after M. Karunanidhi expelled him from the party for demanding an account as the party treasurer. The party is adhering to the policy of socialism and secularism based on the principles of C. N. Annadurai (Anna) collectively coined as Annaism by M.G.R. The party has won a seven-time majority in the Tamil Nadu Legislative Assembly and has emerged as the most successful political outfit in the state's history. It is currently the main opposition party in the Tamil Nadu Legislative Assembly and part of the India-ruling National Democratic Alliance.
From 9 February 1989 to 5 December 2016, the AIADMK was led by the former chief minister of Tamil Nadu J. Jayalalithaa (Amma) as general secretary of the party. She was admired as the Mother of the party by her cadre and was highly popular among the Tamil populace until her death in 2016. From 21 August 2017 to 23 June 2022, the party was led under the dual leadership of the former chief ministers of Tamil Nadu O. Panneerselvam and Edappadi K. Palaniswami as coordinator and joint coordinator respectively.
The party was founded on 17 October 1972, as Anna Dravida Munnetra Kazhagam (ADMK) by M. G. Ramachandran (M.G.R.), a veteran Tamil film star and popular politician. It was set up as a breakaway faction of the DMK led by M. Karunanidhi, then chief minister of Tamil Nadu, owing to personal differences between the two. M.G.R., who wanted to start a new party, then incorporated Anakaputhur Ramalingam into the party, which had registered under the name "ADMK". He then declared, "I joined the party started by an ordinary volunteer" and gave the post of Member of Legislative Council (MLC) to Ramalingam. Later, M.G.R. prefixed the All India (AI) tag to the party's name to save himself from IT raids and protect the party during the Maintenance of Internal Security Act (MISA). Since its inception, the relationship between the AIADMK and DMK has been marked by mutual contempt. M.G.R. used his fan network to build the party cadre; he claims his party recruited more than a million members in the first two months. C. N. Annadurai's ideologue and movie producer turned politician R. M. Veerappan was the key architect in unifying M.G.R. fan clubs and further consolidating the party structure in the 1970s. Other key leaders, such as Nanjil K. Manoharan and S. D. Somasundaram played major roles in consolidation. Pavalar M. Muthusamy was elected the first presidium chairman of the party. The party's first victories were the wins of Maya Thevar in the Dindigul parliamentary bye-election in May 1973 and of C. Aranganayagam in the Coimbatore West assembly bye-election a year later. On 2 April 1973, the AIADMK emerged as the third-largest political party in Tamil Nadu, represented by 11 MLAs in the assembly. By January 1976, the AIADMK had emerged as the second-largest political party in Tamil Nadu, with 16 MLAs in the assembly. By supporting the National Emergency between 1975 and 1977, the AIADMK grew close to the Indian National Congress party.