Helena High School is a public high school for grades 9 through 12 located in Helena, Montana, United States. It is part of the Helena Public School District. Founded in September 1876, it is the oldest high school in the state of Montana. A new building was completed in August 1935 and it was almost destroyed a few months later in the 1935 Helena earthquake. In 1955, the building became Helena Junior High School and Helena High School moved into its present location at 1300 Billings Avenue, just off Montana Avenue.

Helena is the capital city of the U.S. state of Montana and the seat of Lewis and Clark County.