Stuart Country Day School of the Sacred Heart is an independent all-girls Catholic country day school located in Princeton, in Mercer County, New Jersey, United States, that serves students from pre-kindergarten through twelfth grade. Stuart is divided into a co-educational Early Childhood Program, a Lower School for junior kindergarten through grade 4, a Middle School for grades 5 through 8, and an Upper School for grades 9 through 12. The school was named for Janet Erskine Stuart. The school operates under the auspices of the Roman Catholic Diocese of Trenton.