Duncanville High School is a secondary school located in Duncanville, Texas, United States, in the Dallas-Fort Worth area. The school is a part of Duncanville Independent School District. The school includes grades 9 through 12. The high school campus is the second largest in the nation in terms of campus size. The district, and therefore the high school, serves almost all of the city of Duncanville, as well as portions of Cedar Hill, DeSoto, and a small portion of southwest Dallas. For the 2018–2019 academic year, the school received a B grade from the Texas Education Agency.