Southwestern High School was a public high school located near the village of Patriot, Ohio.

It opened in 1965 and closed in 1992 when it was consolidated into River Valley High School.

The Southwestern Local School District was formed in 1965 when the school districts from Centerville and Patriot Cadmus consolidated.

At that time, the other high schools were closed and their students were transported to the Kyger Creek High School building, which was renamed River Valley High School.

In 1993, Buckeye Rural Electric Cooperative purchased the former Southwestern High School and remodeled the building for occupation by November 1994.