Cheng Yen (Chinese: ????; pinyin: Zhèngyán Fashi) is a Taiwanese Buddhist nun (bhikkhuni), teacher, and philanthropist.
She was a student and follower of Ying Shun, a major figure in the development of Humanistic Buddhism in Taiwan.
In 1966, Cheng Yen founded the Buddhist Compassion Relief Tzu Chi Foundation, ordinarily referred to as Tzu Chi.
Cheng Yen started Tzu Chi as a group of thirty housewives who saved money to help needy families.
The organization later became one of the largest humanitarian organizations in the world, eventually becoming the largest Buddhist organization in Taiwan.
Cheng Yen is considered to be one of the most influential figures in the development of modern Taiwanese Buddhism.
In Taiwan, she is popularly referred to as one of the "Four Heavenly Kings" of Taiwanese Buddhism, along with her contemporaries Sheng-yen of Dharma Drum Mountain, Hsing Yun of Fo Guang Shan and Wei Chueh of Chung Tai Shan.