Seon or Korean Zen Buddhism (Korean: 선; Hanja: 禪; Korean pronunciation: [sʌn]) is the Korean name for Chan Buddhism, a branch of Mahāyāna Buddhism commonly known in English as Zen Buddhism. Seon is the Sino-Korean pronunciation of Chan, (Chinese: 禪; pinyin: chán) an abbreviation of 禪那 (chánnà), which is a Chinese transliteration of the Sanskrit word of dhyāna ("meditation"). Seon Buddhism, represented chiefly by the Jogye and Taego orders,is now the most common type of Buddhism found in Korea.

A main characteristic of Seon Buddhism is the use of the method of meditation, Ganhwa Seon(看話禪). A Korean monk, Jinul accepted partially a meditative method of Chan Buddhism in 1205. In Chan Buddhism, hwadu (화두; 話頭) is a short phrase to ground oneself during meditation. Jinul addressed a doctrine of Sagyo Yiepseon (사교입선; 捨敎入禪) that monks should live an inborn life after learning and forgetting all creeds and theories. Within the doctrine of Jinul, hwadu is the witnessing of truthful meaning in everyday life.

During the Goryeo dynasty Jinul strongly influenced Korean Buddhism. He was the first monk to be appointed a national teacher and advisor by the king, having written a book presenting the Seon tradition from the Song dynasty. And this Seon tradition preserved well to this day, after Taego Bou brought his Dharma transmission to Goryeo.

The Joseon dynasty suppressed Buddhism in favour of Confucianism. In spite of the suppression, Hyujeong wrote about the three religions (Seon Buddhism, Confucianism, Taoism) in the Joseon dynasty from Seon point of view. He also succeeded to the Dharma transmission. During the Japanese invasions of Korea (1592–98), Hyujeong and Yujeong commanded guerrilla units of monks and took part in diplomacy.

Under annexation by Japan most monks were forced to marry - this lasted about 40 years until the act of purification. During those times, masters like Gyoengheo and Mangong kept Dharma transmission alive.

Entering into the 21st century a common saying in the Korean Buddhist community is "남진제 북송담'(南眞際 北松潭) (Jinje in the south, Songdam in the north).", which refers to the influence of two great Seon masters characterizing this period, namely Jinje and Songdam. Other relevant monks are Seungsahn and Daewon.

Chan was transmitted into Unified Silla (668–935). Beomnang (法朗; fl. 632–646), who studied with the Fourth Patriarch Dayi Daoxin, was the first to bring the teachings to Korea. Beomnang transmitted his teachings to Sinhaeng (神行; 704–779), who also studied in China. Sinhaeng studied with Puji (651–739), a successor of Yuquan Shenxiu, the head of the East Mountain Teaching of Chan. Seon was further popularized by Doui (道義) at the beginning of the ninth century.

Seon was gradually further transmitted into Korea, as Korean monks of predominantly Hwaeom and Yogacara background^{[citation needed]} began to travel to China to study the Hongzhou school of Mazu Daoyi and his successors and the Rinzai school of Linji Yixuan. Mazu's successors had numerous Korean students, some of whom returned to Korea and established their own schools at various mountain monasteries with their leading disciples.