Lin Daiyu (林黛玉) is one of the principal characters of Cao Xueqin's classic Chinese novel Dream of the Red Chamber. She is described as having been sickly and prone to illness since childhood. She becomes a well-educated and intelligent young woman who is portrayed in a highly sympathetic light. The romance between Daiyu and Jia Baoyu forms one of the the main threads of the book and in many readers' eyes, Lin Daiyu is the book's leading lady.

Daiyu is an emotional young woman, prone to mood swings. Her character complements that of her cousin, Xue Baochai. Indeed, it has been suggested that the two women are complements of one another - each has exactly the attributes of Cao Xueqin's ideal woman which the other lacks.