Petronille de Grandmesnil was born circa 1134 in Leicestershire, England, United Kingdom to Guillaume de Grandmesnil (c1100-c1147) and Beatrix de Rye and died 1 April 1212 of unspecified causes. She married Robert de Beaumont, 3rd Earl of Leicester (1130-1190) .
Children
| Name | Birth | Death | Joined with |
| Robert de Beaumont, 4th Earl of Leicester (c1156-1204) | 1156 | 21 October 1204 | Loretta de Braose |
| Roger de Beaumont (c1158-1202) | |||
| Amicia Beaumont (c1155-1215) | 1155 | September 1215 | Simon IV de Montfort (c1156-1187) Guillaume II des Barres |
| Margaret Beaumont (1180-1236) | 1180 Hampshire, England | 12 January 1236 Northamptonshire, England | Saer de Quincy, 1st Earl of Winchester (c1170-1219) |
Residences
Footnotes (including sources)
| ‡ General |