Saint Peter's Preparatory School (also known as Saint Peter's Prep or simply Prep) is an independent, preparatory, and all-male day school located in Jersey City, in Hudson County in the U.S. state of New Jersey, within the Archdiocese of Newark. Founded in 1872 by the Jesuits, it is operated as part of the Jesuit East Province. The school has been accredited by the New Jersey Association of Independent Schools.

Students enroll from counties in Central and Northern New Jersey, as well as from nearby New York City. The school has a faculty of 83 that includes two Jesuits, 71 lay teachers, and 10 counselors, seven of whom work on college placement. Tuition for the 2025–26 school year is $24,551, while mandatory fees total $1,300.

As of the 2023–24 school year, the school had an enrollment of 863 students and 76.3 classroom teachers (on an FTE basis), for a student–teacher ratio of 11.3:1. The school's student body was 45.4% (392) White, 26.3% (227) Hispanic, 11.5% (99) Asian, 9.7% (84) Black 6.6% (57) two or more races and 0.5% (4) Native Hawaiian / Pacific Islander.