Grundy High School is a public high school located east of Grundy, Virginia on Slate Creek in Buchanan County, Virginia. It is part of the Buchanan County Public Schools system. Athletic teams compete in the Virginia High School League's Black Diamond District in the Region D Conference. Grundy is a National Blue Ribbon School.

Following the closing of Grundy Junior High at the end of the 1994-1995 school year, the High School's name was changed from Grundy Senior High School to Grundy High School.

At the end of the 2025-2026 school year, Grundy Senior High School will close and consolidate with the two other current Buchanan County High Schools to create the new Southern Gap High School.