| School
| Location
| Membership Date
|
| Casady School |
|
Oklahoma City |
Oklahoma |
|
June 1992 |
| Good Shepherd Episcopal School |
|
Dallas |
Texas |
|
April 2000 |
| Greenhill School |
|
Dallas |
Texas |
|
November 1989 |
| ISAS Headquarters |
|
Fort Worth |
Texas |
|
November 1989 |
| Keystone School |
|
San Antonio |
Texas |
|
November 1990 |
| St. John's Episcopal School |
|
Dallas |
Texas |
|
January 2000 |
| St. John's School |
|
Houston |
Texas |
|
August 1990 |
| St. Stephen's Episcopal School |
|
Austin |
Texas |
|
April 1990 |
| The Episcopal School of Dallas |
|
Dallas |
Texas |
|
September 1999 |
| The Hockaday School |
|
Dallas |
Texas |
|
September 1999 |
| The Lamplighter School |
|
Dallas |
Texas |
|
October 1991 |
| The Parish Episcopal School |
|
Dallas |
Texas |
|
April 2000 |
| Trinity School of Midland |
|
Midland |
Texas |
|
October 1990 |
| Ursuline Academy of Dallas |
|
Dallas |
Texas |
|
January 2004 |
