Pongal, also called as Tamizhar Thirunaal (festival of Tamils) or Makara Sankranti elsewhere in India, a four-day harvest festival is one of the most widely celebrated festivals throughout Tamil Nadu. The Tamil language saying Thai Pirandhal Vazhi Pirakkum — literally meaning, the birth of the month of Thai will pave way for new opportunities — is often quoted with reference to this festival. The first day, Bhogi Pongal, is celebrated by throwing away and destroying old clothes and materials by setting them on fire to mark the end of the old and emergence of the new. The second day, Surya Pongal, is the main day which falls on the first day of the tenth Tamil month Thai (14 January or 15 January in western calendar). The third day, Maattu Pongal, is meant to offer thanks to the cattle, as they provide milk and are used to plough the lands. Jallikattu, a bull taming contest, marks the main event of this day. During this final day, Kaanum Pongal — the word "kaanum", means 'to view' in Tamil.

The first month in the Tamil calendar is Chitterai and the first day of this month in mid-April is celebrated as Tamil New Year. Thiruvalluvar Calendar is 31 years ahead of Gregorian Calendar, that is 2000 AD in Gregorian calendar is represented as 2031 in Thiruvalluvar Calendar. Aadi Perukku is celebrated on the 18th day of the Tamil month Aadi, which celebrates the rising of the water level in the river Cauvery. Apart from these major festivals, in every village and town of Tamil Nadu, the inhabitants celebrate festivals for the local gods once a year and the time varies from place to place. Most of these festivals are related to the goddess Maariyamman, the mother goddess of rain.

Additional major Hindu festivals including Deepavali ( Death of Narakasura), Ayudha Poojai, Saraswathi Poojai (Dasara), Krishna Jayanthi and Vinayaka Chathurthi are celebrated widely. Ayya Vaikunda Avataram, is celebrated predominantly in the southern districts. In addition, Christmas, Eid ul-Fitr, Easter and Bakrid are celebrated by Christians and Muslims in the state.