| 361 | 6 | T R Leger School of Adult & Continuing Secondary School | Upper Canada DSB | Cornwall | Public | 6.9 | — | 6.9 | 4.3 | +2.6 ↑ | Visit |
| 415 | 6 | St Joseph's Secondary School | CDSB of Eastern Ontario | Cornwall | Catholic | 6.6 | 6.6 | 5.9 | 5.5 | +1.1 ↑ | Visit |
| 441 | 12 | École secondaire publique L'Héritage | CÉP de l'Est de l'Ontario | Cornwall | Public | 6.5 | 6.5 | 7.1 | 8.3 | -1.8 ↓ | Visit |
| 534 | 7 | École secondaire catholique La Citadelle | CSDC de l'Est ontarien | Cornwall | Catholic | 6.0 | 6.0 | 6.9 | 6.4 | -0.4 ↓ | Visit |
| 738 | 21 | Cornwall Collegiate and Vocational School | Upper Canada DSB | Cornwall | Public | 4.1 | 4.1 | 4.0 | 4.5 | -0.4 ↓ | Visit |
| 751 | 22 | St Lawrence Secondary School | Upper Canada DSB | Cornwall | Public | 3.7 | 3.7 | 3.9 | 3.4 | +0.3 ↑ | Visit |
| 769 | 10 | St Matthew Catholic Secondary School | CDSB of Eastern Ontario | Cornwall | Catholic | 1.6 | 1.6 | 2.3 | 2.1 | -0.5 ↓ | Visit |