Dalit (English: /ˈdælɪt/ from Sanskrit: दलित meaning "broken/scattered") is a term used for untouchables and outcasts, who represent the lowest stratum of the castes in the Indian subcontinent. They are also called Harijans. Dalits were excluded from the fourfold varna of the caste hierarchy in Hinduism and were seen as forming a fifth varna, also known by the name of Panchama.

Several scholars have drawn parallels between Dalits and the Burakumin of Japan, the Baekjeong of Korea and the peasant class of the medieval European feudal system. Dalits predominantly follow Hinduism with significant populations following Buddhism, Sikhism, Christianity, and Islam. The constitution of India includes Dalits as one of the Scheduled Castes; this gives Dalits the right to protection, affirmative action (known as reservation in India), and official development resources.

The term Dalit is for those called the "untouchables" and others that were outside of the traditional Hindu caste hierarchy. Economist and reformer B. R. Ambedkar (1891–1956) said that untouchability came into Indian society around 400 CE, due to the struggle for supremacy between Buddhism and Brahmanism. Some Hindu priests befriended untouchables and were demoted to low-caste ranks. Eknath, who was an excommunicated Brahmin, fought for the rights of untouchables during the Bhakti period.

In the late 1880s, the Marathi word 'Dalit' was used by Jyotirao Phule for the outcasts and untouchables who were oppressed and broken in the Hindu society. Dalit is a vernacular form of the Sanskrit दलित (dalita). In Classical Sanskrit, this means "divided, split, broken, scattered". This word was repurposed in 19th-century Sanskrit to mean "(a person) not belonging to one of the four Varnas". It was perhaps first used in this sense by Pune-based social reformer Jyotirao Phule, in the context of the oppression faced by the erstwhile "untouchable" castes from other Hindus. The term Dalits was in use as a translation for the Indian census classification of Depressed Classes prior to 1935. It was popularised by Ambedkar, himself a Dalit, who included all depressed people irrespective of their caste into the definition of Dalits. It covered people who were excluded from the fourfold varna system of Hinduism and thought of themselves as forming a fifth varna, describing themselves as Panchama. In the 1970s its use was invigorated when it was adopted by the Dalit Panthers activist group.

Socio-legal scholar Oliver Mendelsohn and political economist Marika Vicziany wrote in 1998 that the term had become "intensely political ... While the use of the term might seem to express appropriate solidarity with the contemporary face of Untouchable politics, there remain major problems in adopting it as a generic term. Although the word is now quite widespread, it still has deep roots in a tradition of political radicalism inspired by the figure of B. R. Ambedkar." They went on to suggest that its use risked erroneously labelling the entire population of untouchables in India as being united by a radical politics. Anand Teltumbde also detects a trend towards denial of the politicised identity, for example among educated middle-class people who have converted to Buddhism and argue that, as Buddhists, they cannot be Dalits. This may be due to their improved circumstances giving rise to a desire not to be associated with what they perceive to be the demeaning Dalit masses.

James Lochtefeld, a professor of religion and Asian studies, said in 2002 that the "adoption and popularization of [the term Dalit] reflects their growing awareness of the situation, and their greater assertiveness in demanding their legal and constitutional rights".

India's National Commission for Scheduled Castes considers official use of dalit as a label to be "unconstitutional" because modern legislation prefers Scheduled Castes; however, some sources say that Dalit has encompassed more communities than the official term of Scheduled Castes and is sometimes used to refer to all of India's oppressed peoples. A similar all-encompassing situation prevails in Nepal.

Scheduled Castes is the official term for Dalits in the opinion of India's National Commissions for Scheduled Castes (NCSC), who took legal advice that indicated modern legislation does not refer to Dalit and that therefore, it says, it is "unconstitutional" for official documents to do so. In 2004, the NCSC noted that some state governments used Dalits rather than Scheduled Castes in documentation and asked them to desist.