Fanny Fern, born Sara Willis (July 9, 1811 – October 10, 1872), was an American newspaper columnist, humorist, novelist, and author of children's stories in the 1850s-1870s. Fern's great popularity has been attributed to her conversational style and sense of what mattered to her mostly middle-class female readers. By 1855, Fern was the highest-paid columnist in the United States, commanding $100 per week for her New York Ledger column.

A collection of her columns published in 1853 sold 70,000 copies in its first year. Her best-known work, the fictional autobiography Ruth Hall (1854), has become a popular subject among feminist literary scholars.