Yoga as a philosophical system is one of six orthodox systems of Indian philosophy, but the practice of yoga is considerably older. This paper will present some of the examples of early ideas about yoga found in the upaniṣads, Mokṣadharmaparvan and Bhāgavad-Gītā, as well as certain examples of connection between Buddhism and Yoga philosophy. The foundational text of Yoga system, the Yoga-sūtra, was written roughly between 350. and 450. C.E., and is attributed to Patañjali. The philosophy of Yoga is closely related to the philosophy of Sāṃkhya, a dualism that distinguishes principle of consciousness and principle of materiality that includes mental phenomena as well. Identification of consciousness with mental phenomena is a result of ignorance which is considered to cause suffering and rebirth. Goals of both of these philosophies are attainment of discriminative knowledge and spiritual liberation. While attainment of these goals for Sāṃkhya is a result of an intellectual endeavour, Yoga is primarily focused on meditative practice which results in experiential insight. Discriminative knowledge and spiritual liberation are attained by the cessation of fluxtuations of awareness which is a result of methodical practice. This paper will present a yoga practice that consists of eight constituent parts (yama, niyama, āsana, prāṇāyama, pratyāhāra, dhāraṇā, dhyāna and samādhi) and its philosophical foundations.