St. Joseph High School, also known as St. Joe's, is an independent, all-boys Roman Catholic college preparatory school located on a 70-acre (280,000 m2) campus in Metuchen and Edison, in Middlesex County, New Jersey, United States. The school draws students from an area encompassing over forty school districts and over seventy grammar schools in Middlesex, Somerset, and Union counties, as well as other outlying areas. It is located in the Roman Catholic Diocese of Metuchen. The school has been accredited by the Middle States Association of Colleges and Schools Commission on Elementary and Secondary Schools since 1968.