The Southern Indiana Athletic Conference (SIAC) is a high school athletic conference based in Evansville, Indiana. Five of the conferences 10 schools; Bosse, Central, Harrison, North, and Reitz; comprise the public Evansville Vanderburgh School Corporation. Mater Dei and Memorial are private Catholic high schools run by the Roman Catholic Diocese of Evansville, and the largest member is Castle, a public school located in neighboring Newburgh in Warrick County under the Warrick County School Corporation. The league was founded in 1936, and at one point stretched far across southern and western Indiana: from Mount Vernon in the west to New Albany in the east, and from Evansville in the south to Terre Haute in the north. Jasper and Vincennes Lincoln announced in May 2019 that they would leave the disbanding Big Eight Conference to rejoin the Southern Indiana Athletic Conference beginning with the 2020–21 season.

Member schools

Former members

Membership timeline

Conference championships

Football

Boys basketball

Boys cross country

Wrestling

Boys soccer

Boys tennis

Boys swimming

Baseball

Boys golf

Boys track and field

Volleyball

Girls basketball

Girls cross country

Girls soccer

Girls tennis

Girls swimming

Softball

Girls golf

Girls track and field

State titles

John H. Castle Knights

Evansville Benjamin Bosse Bulldogs

Evansville Central Bears

None

Evansville William Henry Harrison Warriors

Evansville Mater Dei Wildcats

Evansville North Huskies

• = indicates title won before IHSAA State Tournament was initiated

Evansville Francis Joseph Reitz Panthers

• = indicates title won before IHSAA State Tournament was initiated

• = indicates title sanctioned by the Indiana High School Bowling Association

Evansville Reitz Memorial Tigers

• = indicates title won before IHSAA State Tournament was initiated

Jasper Wildcats

Vincennes Lincoln Alices

Neighboring conferences