William IV (c. 1030 – 1100) was the fifth Marquis of Montferrat from 1084.
The date of William's birth is unknown, but it most likely took place between 1030 and 1035. He was the eldest son of Otto II and Constance of Savoy.
| William IV, Marquis of Montferrat | |
|---|---|
| Marquis of Montferrat | |
| Reign | 20 November 1084 – 1100 |
| Predecessor | Otto II |
| Successor | Rainier |
| Born | 1030–1035 |
| Died | 1100 (aged 64–70) |
| Spouse | Otta di Aglié |
| Issue | Rainier |
| House | Aleramici |
| Father | Otto II |
| Mother | Constance of Savoy |