Francis Magalona
Oahu Interscholastic Association
Nevada Interscholastic Activities Association
Pennsylvania Interscholastic Marching Band Association
Hudson County Interscholastic League
Interscholastic Equestrian Association
New Jersey State Interscholastic Athletic Association
Prairie View Interscholastic League
Pennsylvania Interscholastic Athletic Association
Muslim Interscholastic Tournament
University Interscholastic League
New York Interscholastic Athletic Association
District of Columbia Interscholastic Athletic Association
Connecticut Association of Schools
Rhode Island Interscholastic League
California Interscholastic Federation
Delaware Interscholastic Athletic Association
Maui Interscholastic League
Interscholastic League of Honolulu
Western Pennsylvania Interscholastic Athletic League
Metropolitan Interscholastic Conference
Portland Interscholastic League
Philadelphia Public League
North Jersey Interscholastic Conference
Kauai Interscholastic Federation
Union County Conference
New England Interscholastic Rowing Association
Interscholastic Association of Southeast Asian Schools
Massachusetts Interscholastic Athletic Association
Interscholastic Sailing Association
New Jersey Interscholastic Athletic Association
Pioneer Valley Interscholastic Athletic Conference
Sussex County Interscholastic League
Virginia Interscholastic Association
Washington Interscholastic Activities Association
Northern New Jersey Interscholastic League
Southern Interscholastic Press Association
North Bergen Interscholastic Athletic League
Georgia Interscholastic Association
Fairfield County Interscholastic Athletic Conference
Arizona Interscholastic Association
Maryland Interscholastic Athletic Association
Florida Interscholastic Athletic Association
Louisiana Interscholastic Athletic and Literary Organization
National Interscholastic Cycling Association
Long Island Interscholastic Athletic League
Interscholastic Athletic Association of Maryland
High school ice hockey in Pennsylvania
Big Island Interscholastic Federation
Alabama High School Athletic Association
New Hampshire Interscholastic Athletic Association
List of University Interscholastic League events
Kansas City Interscholastic Conference
New Brunswick Interscholastic Athletic Association
CIF North Coast Section
Wisconsin Interscholastic Athletic Association
High school football
MIAA Division 1A boys' ice hockey tournament
CIF California State Meet
Ohio Southwest Region defunct athletic conferences
Amateur sports