Hatha Yoga, which literally means union through discipline of force, is a school of Yoga that stresses mastery of the body as a way of attaining a state of spiritual perfection in which the mind is withdrawn from external objects. Hatha Yoga has grown in popularity in the West as a form of exercise that develops strength, flexibility, bodily relaxation, and mental concentration.

Hatha Yoga traces its origins especially to Gorakhnath, the legendary 11th-century founder of the Kanphata Yogis, but it is believed to date back at least as far as Patanjali (2nd century bce or 5th century ce), author of the Hindu classics the Yoga-sutras. However, this is believed because Patanjali refers to the word asana, which contrary to the popular belief that this refers to yoga postures, the word actually means to be seated in a firm, pleasant, and relaxed position, which is ideal for meditation, not postures.

Yoga postures, while having many great benefits, is not what Patanjali was referring to in his sutras. The purpose of asana is to enable one to rise above body-consciousness. A straight spine is necessary, for when meditating the energy must be allowed to rise up the spine freely. One may consider that they have mastered asana if they can remain completely motionless, with a straight, upright spine for three hours. Motionlessness will enable them to become aware of the inner energies in the body.

Popular thinking in the West (an all-too-common expression now), is that Hatha yoga is about balancing the body and mind. With 'ha' representing the esoteric sun, and that the moon, and the practice of Hatha yoga aiming to join, yoke, or balance these two energies.

A yoga class described as 'Hatha' will typically involve a set of physical postures and breathing techniques, practised more slowly and with more static posture holds than perhaps a Vinyasa flow or Ashtanga class.

Hatha yoga is a popular tradition that reinforces equilibrium, flexibility and strength. The primary elements of the Western practice are yoga poses (asanas) and breath control; however, there are six other elements, or "limbs," involved in the full enjoyment of the discipline.