The Old Killingly High School is a historic school building on 185 Broad Street in the Danielson section of Killingly, Connecticut. It is a two story brick Classical Revival structure with a hip roof, built in 1908 and enlarged with side wings in 1927. The building served as the community's high school until 1965, and as its junior high school 1966-88. The school is notable for its architecture and its importance in the educational history of the community.The building was listed on the National Register of Historic Places in 1992.