Dunlap High School was built in 1976. Some of the features in the high school at construction were the following: a large Home Economics Lab, Industrial Arts Department, a spacious and well equipped computer lab and Business Department, a large Chemistry and Biology Lab with a small greenhouse adjacent, a Band and Music room with built-in risers for Chorus and Band, two foreign languages, including French and Spanish, plus four years of English Grammar and Literature, a Mathematics Department and one for Fine Arts. As for sports, there was a large indoor heated swimming pool, an outdoor all-weather track, plus the new football field with bleachers, softball, baseball, football, swimming, and track. There was also a large library, as well as a large Commons or Cafeteria that is located just beyond the foyer, where, each year, the Dunlap High School graduates meet for the annual Alumni Banquet.

In 1990, an addition was added on to the new high school which has now been turned into two classrooms.

In 1998, the following additions were made to Dunlap High School: six new classrooms, new library/technology center, additional locker room space, additional cafeteria space, and enhanced student services area.

In August, 2005, the following renovation was completed to the high school: Freshman Academy with ten new classrooms, new auditorium with an 1100 seat capacity, fine arts center for the band, chorus, and visual arts, auxiliary gymnasium, and updated cafeteria which includes a food court.

In September, 2010, ten additional classrooms were added to Dunlap High School, including two computer labs and a science lab. This was the Phase 1 constructions at Dunlap High School.

In September 2011, $5,000,000 in athletic upgrades were completed including artificial turf football field, new soccer complex, concession stands, and a new tennis complex.

In August 2014, Dunlap High School completed a two story addition to the current school (Phase 2 construction). The additions included a renovated cafeteria, updated locker rooms, weight room, new science labs, computer labs, robotics lab, and a capacity for 1,800 students.