Yoga philosophy is one of the six major orthodox schools of Hinduism. Ancient, medieval and most modern literature often refers to Yoga-philosophy simply as Yoga, and it is only at the end of the first millennium CE that Yoga is mentioned as a separate school of thought in Indian texts, distinct from Samkhya. The systematic collection of ideas of Yoga-philosophy is found in the Yoga Sutras of Patanjali, a key text of Yoga-philosophy which has influenced all other schools of Indian philosophy.

The metaphysics of Yoga is built on the same dualist foundation as the Samkhya school. The universe is conceptualized as composed of two realities in the Samhkya-Yoga schools: Puruṣa (witness-consciousness) and prakriti (mind, cognition, and matter). Jiva (a living being) is considered as a state in which puruṣa is bonded to prakriti in some form, in various permutations and combinations of various elements, senses, feelings, activity and mind. During the state of imbalance or ignorance, one or more constituents overwhelm the others, creating a form of bondage. The end of this bondage is called liberation, or moksha, by both the Yoga and Samkhya schools of Hinduism, and can be attained by insight and self-restraint.

The ethical theory of Yoga-philosophy is based on Yamas and Niyama, as well as elements of the Guṇa theory of Samkhya. The epistemology of Yoga-philosophy, like the Sāmkhya school, relies on three of six Pramanas as the means of gaining reliable knowledge. These include Pratyakṣa (perception), Anumāṇa (inference) and Sabda (Āptavacana, word/testimony of reliable sources). Yoga-philosophy differs from the closely related non-theistic/atheistic Samkhya school by incorporating the concept of a "personal, yet essentially inactive, deity" or "personal god" (Ishvara).