The Illinois High School Association (IHSA) is an association that regulates competition of interscholastic sports and some interscholastic activities at the high school level for the state of Illinois. It is a charter member of the National Federation of State High School Associations (NFHS). The IHSA regulates 14 sports for boys, 15 sports for girls, and eight co-educational non-athletic activities. More than 760 public and private high schools in the state of Illinois are members of the IHSA. The Association's offices are in Bloomington, Illinois.

The National Federation of State High School Associations (NFHS) is the body that writes the rules of competition for most high school sports and activities in the United States. NFHS's headquarters are located in White River State Park in Indianapolis, Indiana.