| Father | William DE MONTAGU (1275 - 1319) |
| Mother | Elizabeth DE MONTFORT (1273 - 1354) |
| Sibling | Lady Mary DE MONTAGU (1280 - 1350) |
| Sibling | John MONTAGU (1299 - 1317) |
| Sibling | William MONTAGU (1301 - 1344) |
| Sibling | Simon MONTACUTE, BISHOP OF ELY (1303 - 1345) |
| Sibling | Elizabeth MONTAGU, Prioress of Holywell Priory (1305 - 1359) |
| Sibling | Sir Edward MONTAGU 1st Baron Montagu (1309 - 1361) |
| Sibling | Alice MONTAGUE (1311 - 1346) |
| Sibling | Lady Catherine MONTAGUE (1315 - 1415) |
| Sibling | Hawise MONTAGUE (1317 - 1361) |
| Sibling | Isabella MONTACUTE (1319 - 1390) |