The Saṃdhinirmocana Sūtra (Sanskrit; traditional Chinese: 解深密經; ; pinyin: Jiě Shēnmì Jīng; Tibetan: དགོངས་པ་ངེས་འགྲེལ༏, Wylie: dgongs pa nges 'grel Gongpa Ngédrel) or Sūtra of the Explanation of the Profound Secrets is a Mahāyāna Buddhist text that is classified as belonging to the Yogācāra school of Buddhism. This sūtra was translated from Sanskrit into Chinese four times, the most complete and reliable of which is typically considered to be that of Xuanzang. It also was translated into Tibetan.
The Saṃdhinirmocana Sūtra is variously romanized as Sandhinirmocana Sutra and Samdhinirmocana Sutra.
Like many early Mahāyāna sūtras, precise dating for the Saṃdhinirmocana Sūtra is difficult to achieve. Étienne Lamotte believed that the text was assembled from earlier, independent fragments. Other scholars believe that the apparently fragmentary nature of the early versions of the scripture may represent piecemeal attempts at translation, rather than a composite origin for the text itself. The earliest forms of the text may date from as early as the 1st or 2nd Century CE. The final form of the text was probably assembled no earlier than the 3rd Century CE, and by the 4th Century significant commentaries on the text began to be composed by Buddhist scholars, most notably Asanga.
The Saṃdhinirmocana Sūtra is one of the most important texts of the Yogācāra tradition, and one of the earliest texts to expound the philosophy of Consciousness-only. Divided into ten sections, the sūtra presents itself as a series of dialogues between Gautama Buddha and various bodhisattvas. During these dialogues, the Buddha attempts to clarify disputed meanings present in scriptures of the early Mahāyāna and the early Buddhist schools; thus, the title of the sūtra, which promises to expound a teaching that is "completely explicit" and requires no interpretation in order to be understood.