Upper Darby High School (UDHS) is a four-year public high school located in Upper Darby Township in Delaware County, Pennsylvania. It is part of the Upper Darby School District. Established in 1895, it is the oldest high school in Delaware County. As of the 2023-2024 school year, the school had an enrollment of 4,388 students and 233.23 classroom teachers (on an FTE basis), for a student-teacher ratio of 16.49. The population is diverse, with over 55 nationalities of students. It has a long-established football rivalry with Monsignor Bonner High School, located less than a block away. Upper Darby High School was a part of the inspiration for Upper Darby alumna Tina Fey's movie comedy Mean Girls. The mascot of Upper Darby High is the Royal, which is portrayed as a lion. In previous years, it was a court jester. The school emblem is the royal oak tree, the yearbook is named the Oak, and the newspaper is called the Acorn. An Acorn award is rewarded every year at the UDAEF Sweet Night Out Foundation Ball in February. Upper Darby Senior High School is one of the largest high schools in Pennsylvania by enrollment. The High School is also home to the Upper Darby Performing Arts Center, and the Summer Stage program.

Campus

The campus is adjacent to, but not within, the Drexel Hill census-designated place. It has a Drexel Hill postal address.

Demographics

Arts

Upper Darby High School is home to the Upper Darby Performing Arts Center, a nearly 1,800-seat theater that hosts not only school functions, but also between 200 and 400 events annually. During the summer, the arts center hosts the largest summer theater group in Delaware County: Summer Stage, with over 200 participants in multiple musicals. Harry Dietzler founded the Summer Stage program in 1976.

Extracurriculars

Upper Darby High School offers a wide variety of clubs, activities and an extensive sports program.

Sports

Upper Darby sports teams compete in the Central League. The District funds: According to PIAA directory July 2012

Notable alumni

Upper Darby High School's Wall of Fame committee recognizes individuals who have become leaders in their industries. Alumni recognized on Upper Darby High School's Wall of Fame members are indicated with WoF after their biographical summary: