The Old Stonington High School is a historic school building at 25 Orchard Street in Stonington, Connecticut. It is a 2-1/2 story brick Second Empire structure, with a mansard roof and a four-story tower above its entrance. It was built in 1888, and nearly doubled in size by the construction of an adjacent wing in 1903. The building was listed on the National Register of Historic Places in 1978; it has been converted to residential use.
This building is not to be confused with the town's modern high school of the same name in Pawcatuck.