Ātman (; Sanskrit: आत्मन्) is a Sanskrit word that refers to the (universal) Self or self-existent essence of individuals, as distinct from ego (Ahamkara), mind (Citta) and embodied existence (Prakṛti). The term is often translated as soul, but is better translated as "Self," as it solely refers to pure consciousness or witness-consciousness, beyond identification with phenomena. In order to attain moksha (liberation), a human being must acquire self-knowledge (Atma Gyaan or Brahmajnana).

Atman is a central concept in the various schools of Indian philosophy, which have different views on the relation between Atman, individual Self (Jīvātman), supreme Self (Paramātmā) and, the Ultimate Reality (Brahman), stating that they are: completely identical (Advaita, Non-Dualist), completely different (Dvaita, Dualist), or simultaneously non-different and different (Bhedabheda, Non-Dualist + Dualist).

The six orthodox schools of Hinduism believe that there is Ātman in every living being (jiva), which is distinct from the body-mind complex. This is a major point of difference with the Buddhist doctrine of Anatta, which holds that in essence there is no unchanging essence or Self to be found in the empirical constituents of a living being, staying silent on what it is that is liberated.