Leavenworth High School is a public high school located in Leavenworth, Kansas, operated by Leavenworth USD 453 school district. The school was established in 1865, making it one of the first high schools in Kansas. The school colors are blue and white and the mascot is the "Pioneer". Leavenworth High School offers many extracurricular activities, both athletic and non-athletic.

The district, of which this is the sole comprehensive high school, includes the central portion of Leavenworth city. Additionally, Fort Leavenworth, which is in Fort Leavenworth USD 207, sends its high school students to Leavenworth High (while PK-9 goes to USD 207).