| 2018 NYSAIS Class B Playoff Bracket | ||||
| QUARTERFINAL | SEMI FINAL | FINAL | ||
| February 22, 2018 | February 24, 2018 | February 26, 2018 | ||
| 1 Lawrence Woodmere (17-5) | ||||
| 58-40 | 1 Lawrence Woodmere (18-5) | |||
| @ Highest Seed | ||||
| 8 Trinity (8-12) | ||||
| 56-48 | 1 Lawrence Woodmere (19-5) | |||
| @ Highest Seed | ||||
| 5 Fieldston (13-11) | ||||
| 57-48 | 4 Dwight (17-10) | |||
| @ Fieldston | ||||
| 4 Dwight (16-10) | ||||
| 51-44 | 1 Lawrence Woodmere (20-5) | |||
| @ Fieldston School | Class B Champion | |||
| 3 Leman (11-9) | ||||
| 56-55 | 6 Collegiate (16-10) | |||
| @ Collegiate | ||||
| 6 Collegiate (15-10) | ||||
| 48-41 | 6 Collegiate (17-10) | |||
| @ Collegiate | ||||
| 7 Poly Prep (12-11) | ||||
| 68-63 | 7 Poly Prep (13-11) | |||
| @ Trevor Day | ||||
| 2 Dalton (19-4) | ||||