St. John the Baptist Diocesan High School
| St. John the Baptist Diocesan High School | |
|---|---|
In Fidie et Lentae | |
| Address | |
1170 Montauk Highway , , 11795 United States | |
| Coordinates | 40°41′44″N 73°17′32″W / 40.69556°N 73.29222°W |
| Information | |
| Type | Private, diocesan, high school |
| Motto | Latin: In Fide et Lenitate (In Faith and in Gentleness) |
| Religious affiliation(s) | Roman Catholic |
| Patron saint(s) | Saint John the Baptist |
| Established | 1966 |
| Principal | Vincent Albrecht |
| Chaplain | Fr. David Atanasio, Jr. |
| Teaching staff | 87.1 (FTE) (2017–18) |
| Grades | 9–12 |
| Gender | coeducational |
| Enrollment | 1,394 (2017–18) |
| Average class size | 26–32 students |
| Student to teacher ratio | 24:1 (2023-24) |
| Color(s) | Red White Navy Blue |
| Athletics conference | NSCHSAA & NSCHSGAA |
| Mascot | Cougar |
| Team name | Cougars |
| Rival | St. Anthony's |
| Accreditation | Middle States Association of Colleges and Schools |
| Tuition | $12,000 (2023-24) |
| Affiliation | National Catholic Educational Association (NCEA) |
| Website | stjohnthebaptistdhs |
St. John the Baptist Diocesan High School is a private, Roman Catholic high school in West Islip, New York. It is operated by the Roman Catholic Diocese of Rockville Centre.