Waterloo High School is a public high school in Atwater, Ohio, United States.

Athletic teams compete as the Waterloo Vikings in the Ohio High School Athletic Association as a member of the Mahoning Valley Athletic Conference.

The Waterloo school district was created two years earlier through the merger of the Atwater and Randolph districts on October 15, 1965.

The building on Industry Road opened in September 1968 and was finished & dedicated on January 26, 1969.

This Portage County, Ohio school article is a stub.