Thích Nhất Hạnh ( TIK NAHT HAHN; Vietnamese: [tʰǐk̟ ɲə̌t hâjŋ̟ˀ] , Huế dialect: [tʰɨt̚˦˧˥ ɲək̚˦˧˥ hɛɲ˨˩ʔ]; born Nguyễn Xuân Bảo; 11 October 1926 – 22 January 2022) was a Vietnamese Thiền Buddhist monk, peace activist, prolific author, poet and teacher, who founded the Plum Village Tradition, historically recognized as the main inspiration for engaged Buddhism. Known as the "father of mindfulness", Nhất Hạnh was a major influence on Western practices of Buddhism.

In the mid-1960s, Nhất Hạnh co-founded the School of Youth for Social Services and created the Order of Interbeing. He was exiled from South Vietnam in 1966 after expressing opposition to the war and refusing to take sides. In 1967, Martin Luther King Jr. nominated him for a Nobel Peace Prize. Nhất Hạnh established dozens of monasteries and practice centers and spent many years living at the Plum Village Monastery, which he founded in 1982 in southwest France near Thénac, traveling internationally to give retreats and talks. Nhất Hạnh promoted deep listening as a nonviolent solution to conflict and sought to raise awareness of the interconnectedness of environments that sustain and promote peace. He coined the term "engaged Buddhism" in his book Vietnam: Lotus in a Sea of Fire.

After a 39-year exile, Nhất Hạnh was permitted to visit Vietnam in 2005. In 2018, he returned to Vietnam to his "root temple", Từ Hiếu Temple, near Huế, where he lived until his death in 2022, at the age of 95.