The Tamils (/ˈtæmɪlz, ˈtɑː-/ TAM-ilz, TAHM-), also known by their endonym Tamilar, are a Dravidian ethnic group who natively speak the Tamil language and trace their ancestry mainly to the southern part of the Indian subcontinent. The Tamil language is one of the longest-surviving classical languages, with over two thousand years of written history, dating back to the Sangam period (between 300 BCE and 300 CE). Tamils constitute about 5.7% of the Indian population and form the majority in the South Indian state of Tamil Nadu and the union territory of Puducherry. They also form significant proportions of the populations in Sri Lanka (15.3%), Malaysia (7%) and Singapore (5%). Tamils have migrated world-wide since the 19th century CE and a significant population exists in South Africa, Mauritius, Fiji, as well as other regions such as the Southeast Asia, Middle East, Caribbean and parts of the Western World.

Archaeological evidence from Tamil Nadu indicates a continuous history of human occupation for more than 3,800 years. In the Sangam period, Tamilakam was ruled by the Three Crowned Kings of the Cheras, Cholas and Pandyas. Smaller Velir kings and chieftains ruled certain territories and maintained relationship with the larger kingdoms. Urbanisation and mercantile activity developed along the coasts during the later Sangam period with the Tamils influencing the regional trade in the Indian Ocean region. Artifacts obtained from excavations indicate the presence of early trade relations with the Romans. The major kingdoms to rule the region later were the Pallavas (3rd–9th century CE), and the Vijayanagara Empire (14th–17th century CE).

The island of Sri Lanka often saw attacks from the Indian mainland with the Cholas establishing their influence across the island and across several areas in Southeast Asia in the 10th century CE. This led to the spread of Tamil influence and contributed to the cultural Indianisation of the region. Scripts brought by Tamil traders like the Grantha and Pallava scripts, induced the development of many Southeast Asian scripts. The Jaffna Kingdom later controlled the Tamil territory in the north of the Sri Lanka from 13th to 17th century CE. European colonization began in the 17th century CE, and continued for two centuries until the middle of the 20th century.

Due to its long history, the Tamil culture has seen multiple influences over the years and have developed diversely. The Tamil visual art consists of a distinct style of architecture, sculpture and other art forms. Tamil sculpture ranges from stone sculptures in temples, to detailed bronze icons. The ancient Tamil country had its own system of music called Tamil Pannisai. Tamil performing arts include the theatre form Koothu, puppetry Bommalattam, classical dance Bharatanatyam, and various other traditional dance forms. Hinduism is the major religion followed by the Tamils and the religious practices include the veneration of various village deities and ancient Tamil gods. A smaller number are also Christians and Muslims, and a small percentage follow Jainism and Buddhism. Tamil cuisine consist of various vegetarian and meat items, usually spiced with locally available spices. Historian Michael Wood called the Tamils the last surviving classical civilization on Earth, because the Tamils have preserved substantial elements of their past regarding belief, culture, music, and literature despite the influence of globalization.

Tamil is derived from the name of the language. The people are referred to as Tamiḻar in Tamil language, which is etymologically linked to the name of the language. The origin and precise etymology of the word Tamil is unclear with multiple theories attested to it. Kamil Zvelebil suggests that the term tamiz might have been derived from tam meaning "self" and "-iz" having the connotation of "unfolding sound". Alternatively, he suggests a derivation of tamiz < tam-iz < *tav-iz < *tak-iz, meaning "the proper process (of speaking)". Franklin Southworth suggests that the name comes from tam-miz > tam-iz meaning "self-speak", or "our own speech".

It is unknown whether the term Tamila and its equivalents in Prakrit such as Damela, Damila, or Tamira was first used as a self designation or by outsiders. The Hathigumpha inscription from Udayagiri in Eastern India dated to the second century BCE, describes a T[r]amira samghata (Confederacy of Tamil rulers), which was in existence for the previous 113 years. Epigraphical evidence from the second century BCE mentioning Damela or Dameda from ancient Sri Lanka have been found. In the Buddhist Jataka texts, there is a mention of a Damila-rattha (Tamil dynasty). Greek historian Strabo (first century BCE) mentions that the Roman Emperor Augustus received an ambassador from Pandyan of Dramira. An inscription from Amaravati dated to third century CE refers to a Dhamila-vaniya (Tamil trader).

Archaeological evidence suggests the region was first inhabited by hominids over 400 millennia ago. Artifacts recovered in Adichanallur by the Archaeological Survey of India (ASI) indicate megalithic urn burials, dating from back to 1500 BCE., which are also described in early Tamil literature. Neolithic celts with the Indus script dated between 15th and 20th century BCE indicate the use of early Harappan language. Excavations at Keezhadi have revealed a large urban settlement, with the earliest artefact dated to 580 BCE, during the time of urbanization in the Indo-Gangetic plain. Further epigraphical inscriptions found at Adichanallur use Tamil Brahmi, a rudimentary script dated to 5th century BCE. Potsherds uncovered from Keeladi indicate a script which might be a transition between the Indus Valley script and Tamil Brahmi script used later.

The Sangam period lasted from 3rd century BCE to 3rd century CE with the main source of history during the period coming from the various Sangam literature. Ancient Tamilakam was ruled by a triumvirate of monarchical states, Cheras, Cholas and Pandyas. These kings are referred to as Vāṉpukaḻ Mūvar (Three glorified by heaven) in the Sangam literature. The Cheras controlled the western part of Tamilkam, the Pandyas controlled the south, and the Cholas had their base in the Kaveri delta. They are mentioned in the inscriptions from the Mauryan Empire dated to third century BCE. Kalinga inscriptions from the second century BCE refers to a confederacy of the Tamil kingdoms. The three kings called Vendhar ruled over several hill tribes headed by the Velir chiefs and settlements headed by clan chiefs called Kizhar. The rulers of smaller territories were referred to as Kurunilamannar, with Purananuru mentioning the names of many such chieftains.