The Green Street School is a historic school building at 104 Green Street in Somersworth, New Hampshire. Built in 1890-91, it is a large brick-and-granite structure sited at the top of a hill in a residential neighborhood. Its setting and the slope of its steeply-pitched roof serve to make it appear oversized. It is the oldest school building in the city, and was its most impressive public building. It served as a public school until 1927, and as a parochial high school from 1934 until c. 1970, when the city again assumed ownership of the building. It was converted into residences in 1983-84.