Middletown High School is a public high school located in Middletown, Delaware, United States. It is one of three high schools in the Appoquinimink School District and serves students grades 9–12. It was previously located in what is now the Everett Meredith Middle School building. Originally opened in 1997, the current facility added a two-story wing in the summer of 2002, and an expansion of its cafeteria/lobby to create extra capacity.