Seng-ts'an (c 520-606) was a Chinese Buddhist monk, the third patriarch in Dhyana School of Chinese Buddhism.

We don't know much about his life. However, there are many legends available about him.

At the time of Buddhist execution in China, he supposedly feigned mental illness to avoid execution, and went into hiding for ten years.

One of the earliest Chinese Zen texts - Hsin-hsin-ming is attributed to him.