Shi Nai'an (ca. 1296–1372) was a Chinese writer from Suzhou. Water Margin, one of the Four Great Classical Novels of Chinese literature, is attributed to him.
Little biographical information is known about him.
Traditionally, it was believed that he was a teacher of Luo Guanzhong, the editor or author of Romance of the Three Kingdoms, another of the Four Great Classical Novels.
Some modern scholars doubt that Shi existed or suggest that "Shi Nai'an" was merely a pseudonym for Luo himself.
The Shi Nai'an Literary Prize is named in his honor.