Yunmen Wenyan (Chinese: 雲門文偃; Japanese: Ummon Bun'en; 862 or 864 – 949 CE), was a major Chinese Chan master of the Tang dynasty. He was a dharma-heir of Xuefeng Yicun.
Yunmen founded the Yunmen school, one of the five major schools of Chán (Chinese Zen). The name is derived from Yunmen monastery of Shaozhou where Yunmen was abbot. The Yunmen school flourished into the early Song Dynasty, with particular influence on the upper classes, and eventually culminating in the compilation and writing of the Blue Cliff Record.
The school would eventually be absorbed by the Linji school later in the Song. The lineage still lives on to this day through Chan Master Xuyun (1840–1959).