The Nyaya Sutras is an ancient Indian Sanskrit text composed by Aksapada Gautama, and the foundational text of the Nyaya school of Hindu philosophy.The date when the text was composed, and the biography of its author is unknown, but variously estimated between 6th-century BCE and 2nd-century CE. The text may have been composed by more than one author, over a period of time. The text consists of five books, with two chapters in each book, with a cumulative total of 528 aphoristic sutras, about rules of reason, logic, epistemology and metaphysics.

The Nyaya school of Hinduism influenced all other schools of Hindu philosophy, as well as Buddhism. Despite their differences, these scholars studied with each other and debated ideas, with Tibetan records suggesting that Buddhist scholars spent years residing with Hindu Nyaya scholars to master the art of reasoning and logic. This cooperation has enabled scholars to place the currently surviving version of the Nyayasutras, to a terminus ante quem (completed before) date of about the 2nd century CE, because one of the most famous and established Buddhist scholars of that era, Nagarjuna, explicitly states, "sutra 4.2.25 is addressed against the Madhyamika system" of Buddhism. Other ancient Buddhist texts confirm that Nyayasutras existed before them, and the text is considered the primary text of old Nyaya school of Hinduism.