Jack Kornfield is an American writer and teacher in the Vipassana movement in American Theravada Buddhism. He trained as a Buddhist monk in Thailand, Burma and India, first as a student of the Thai forest master Ajahn Chah and Mahasi Sayadaw of Burma. He has taught mindfulness meditation worldwide since 1974. In 1975, he co-founded the Insight Meditation Society in Barre, Massachusetts, with Sharon Salzberg and Joseph Goldstein, and subsequently in 1987, Spirit Rock Meditation Center in Woodacre, California. Kornfield has worked as a peacemaker and activist, organized teacher training, and led international gatherings of Buddhist teachers including the Dalai Lama.

The Vipassanā movement, also called the Insight Meditation Movement and American Vipassana movement, refers to a branch of modern Burmese Theravāda Buddhism that promotes "bare insight" (sukha-Vipassana) to attain stream entry and preserve the Buddhist teachings, which gained widespread popularity since the 1950s, and to its western derivatives which have been popularised since the 1970s, giving rise to the more dhyana-oriented mindfulness movement.