| School Name | City | Province |
|---|---|---|
| S.A. Cawker | Port Perry | Ontario |
| Sacre Coeur | Georgetown | Ontario |
| Sacred Heart | Guelph | Ontario |
| Sacred Heart | Paris | Ontario |
| Sacred Heart of Jesus | Burlington | Ontario |
| Saginaw | Cambridge | Ontario |
| Salisbury Morse Place | Winnipeg | Ontario |
| Sam Sherratt | Milton | Ontario |
| Samuel Burland | Winnipeg | Manitoba |
| Sandhills | Kitchener | Ontario |
| Sandowne | Waterloo | Ontario |
| San Lorenzo Ruiz | Markham | Ontario |
| Sansome | Winnipeg | Manitoba |
| Scholars' Hall | Kitchener | Ontario |
| Scott Central | Sandford | Ontario |