Tathātā (; Sanskrit: तथाता; Pali: tathatā) is a Buddhist term variously translated as Thusness, Suchness, True Thusness, or True Suchness, referring to the Ultimate Reality, the intrinsic and essential nature of all existences, free from dualistic thinking, conceptualization, and subject–object distinction. It is formless, uncreated, eternal, perfect, unchanging, indestructible, and is the true nature of all phenomena. It represents the genuine reality of existence, which transcends physical forms, physical senses, and intellectual comprehension, indicating a profound insight into the nature of things as they truly are.
Tathātā has a large number of synonyms found in different Buddhist schools, traditions, and scriptures, such as: Emptiness (śūnyatā 空), Reality Realm (bhūta-koṭi 實際、實相), True Suchness (bhūta-tathatā 真如), Dharma Nature (Dharmatā 法爾、法然、法性), Dharma Realm (Dharma-dhātu 法界), Dharma Body (Dharma-kāya 法身), Nirvana (Nirvāṇa 涅槃), Vajra (金剛), Actionlessness (無爲), Dharma Intrinsic Nature (Dharma-svabhāva 法自性、法自然), Buddha-nature (Buddhatā, Buddha-svabhāva 佛性), Tathagata-Treasure (Tathāgata-garbha 如來藏), The True Reality of all phenomena (sarva-dharma-tathatā 諸法實相), etc.
Although it is a significant concept in Mahayana Buddhism, it is also used in the Theravada tradition.