Peddie School was founded in 1864 as the Hightstown Female Seminary, a Baptist preparatory school. Later that year, boys were admitted, and the school began a series of name changes. In 1872, the school took its current name in honor of philanthropist and politician Thomas B. Peddie (1808-89), who gave the school a $25,000 gift.
Peddie School remained coed until 1908, when it was decided, for social and economic reasons, to admit boys only. This standard was reversed in the early 1970s, when girls were readmitted. The school is now coeducational and nondenominational. Wilson Hall (1866-1978) served all the school's needs until 1889, when additional land was acquired and more buildings erected. Peddie's longest-serving head of school, Roger W. Swetland (1898-1934), drew up the master plan to create the central grassy mall. Gifts from Ambassador Walter H. Annenberg ‘27 were used for the construction of two libraries, dormitories, and an athletic center, among other projects. The school has grown to include 57 buildings on a 280-acre campus. In 1993, Annenberg gave $100 million to Peddie, which provided an endowed fund for financial aid, enabling students from every walk of life to receive a Peddie education. The ambassador died in 2002, just after giving the cornerstone gift for the construction of The Walter and Leonore Annenberg Science Center, which was completed in fall 2005.