St. Charles East High School is a public four-year high school located in St. Charles, Illinois, a western suburb of Chicago, Illinois, in the United States. It is part of Community Unit School District 303. The school was known as "St. Charles High School" from its opening in 1977 until fall of 2000 when a second school in the city, St. Charles North High School, was opened. At that time the school name changed to "St. Charles East High School."

St. Charles is a city in DuPage and Kane counties in the U.S. state of Illinois. It lies roughly 40 miles (64 km) west of Chicago on Illinois Route 64. Per the 2020 census, the population was 33,081. The official city slogan is "Pride of the Fox", after the Fox River that runs through the center of town. St. Charles is part of a tri-city area along with Geneva and Batavia, all western suburbs of similar size and socioeconomic condition.