The membership is comprised of Public, French, French Catholic, Catholic and Independent School Boards:

• Hamilton-Wentworth District School Board
• District School Board of Niagara
• Niagara Catholic District School Board
• Grand Erie District School Boards (partial)
• Conseil Scholaire de District Du Centre Sud-Quest
• Couseil Scholaire de District Catholique Centre-Sud
• Independent

The association is divided into four Zones.

• Zone I
• Zone II
• Zone III
• Zone IV

SOSSA is a member of the Ontario Federation of School Athletic Associations (OFSAA). For more information on OFSAA, visit their web page at www.ofsaa.on.ca