Mater Dei Prep: A Catholic Preparatory School (commonly known as "Mater Dei High School") was a four-year Catholic coeducational high school that served students in ninth through twelfth grades, located in the New Monmouth section of Middletown Township, in Monmouth County, New Jersey, United States. As of the 2019–20 school year, the school had an enrollment of 316 students and 28.9 classroom teachers (on an FTE basis), for a student–teacher ratio of 10.9:1. The school's student body was 76.9% (243) White, 12.7% (40) Black, 5.7% (18) Hispanic and 4.7% (15) Asian.