The Gateway Athletic Conference is a Missouri State High School Activities Association recognized high school extracurricular league which includes sixteen schools located in the suburbs of St. Louis.
The conference is divided into three divisions based on enrollment.
The North division includes schools with smaller enrollment, the Central division for medium enrollment schools, and the South division for larger enrollment schools.
Most activities (for example, baseball, softball, track, cross country) compete in four classes, but basketball and football competes in six.
Swimming & Diving compete in two classes.