| Mark T. Sheehan High School | |
| Sister School: | Lyman Hall High School |
| District: | Wallingford Public Schools |
| Schooltype: | High School |
| Category: | High school |
| Ceeb: | 070813 |
| Principal: | Enzo Zocco |
| Teaching Staff: | 69.70 |
| Enrollment: | 722 (2022–23)[1] |
| Ratio: | 10.36 |
| Grades: | 9–12 |
| Streetaddress: | 142 Hope Hill Rd |
| County: | New Haven County |
| State: | Connecticut |
| Zipcode: | 06492 |
| Country: | United States |
| Coordinates: | 41.4855°N -72.836°W |
| Colors: | Maroon and gold |
| Athletics: | Football, basketball, baseball, softball, volleyball, ice hockey, field hockey lacrosse, track and field, cross country, soccer, tennis |
| Mascot: | Titans |
Mark T. Sheehan High School is a public high school located at 142 Hope Hill Road, Wallingford, Connecticut. It is part of the Wallingford Public School System, and one of two public high schools in Wallingford, Lyman Hall High School being the other. Its official colors are burgundy and gold. [2]
Sheehan is known for having started the tradition known as powderpuff. The first powderpuff game was played in Wallingford between Sheehan and Lyman Hall. The School is named after Dr. Mark T. Sheehan, a medical officer during World War I, he had also practiced medicine in Wallingford and was known to never deny service to anyone including patients who could not afford care. [3]