Arni is a state assembly constituency in Tiruvannamalai district of Tamil Nadu, India, which includes the city of Arni. Its State Assembly Constituency number is 67. Until and including the 2006 elections, the constituency was part of Vellore Lok Sabha constituency for national elections to the Parliament of India; thereafter, it has been part of Arani Lok Sabha constituency. It is one of the 234 State Legislative Assembly Constituencies in Tamil Nadu, in India.