William FitzWarin | |
|---|---|
 Arms of William FitzWarin.
Quarterly by fess indented argent and sable. | |
| Died | 1299 |
| Resting place | Greyfriars, London |
| Nationality | English |
| Spouse(s) | Maria de Ergadia, daughter of Eóghan of Argyll |
Sir William FitzWarin (died c. 1299) was an English soldier active during the First War of Scottish Independence. He was the constable of Urquhart Castle (1296-1297) and after the English defeat at the Battle of Stirling Bridge on 11 September 1297, he was appointed constable of Stirling Castle, which he later surrendered and was imprisoned in Dumbarton Castle.