| Peter I | |
|---|---|
 Peter represented on a window in Chartres Cathedral | |
| Duke of Brittany | |
| Reign | 1213–1221 (as duke) 1221–1237 (as regent) |
| Predecessor | Alix |
| Successor | John I |
| Co-ruler | Alix |
| Born | c. 1187 |
| Died | 26 May 1250 (aged 63) |
| Spouses |
|
| Issue |
|
| House | Dreux |
| Father | Robert II, Count of Dreux |
| Mother | Yolande de Coucy |
Peter I (French: Pierre; c. 1187 – 26 May 1250), also known as Peter Mauclerc, was Duke of Brittany jure uxoris from 1213 to 1221, and regent of the duchy for his minor son John I from 1221 to 1237. As duke he was also 1st Earl of Richmond from 1218 to 1235.