| Father | Matthew DE FURNEAUX (1253 - 1316) |
| Mother | Matilda DE RALEIGH (1270 - 1331) |
| Sibling | Simon DE FURNEAUX (1294 - 1350) |
| Sibling | Sir Walter FURNEAUX of Holford (1280 - ) |
| Sibling | Dionisia DE FURNEAUX (1285 - ) |
| Sibling | Matilda DE FURNEAUX (1287 - 1358) |
| Sibling | Henry DE FURNEAUX (1292 - ) |
| Sibling | Elianor DEFURNEAUX (1293 - 1390) |
| Sibling | Joan FURNEAUX (1293 - ) |
| Sibling | Thomas de FURNEAUX (1297 - ) |
| Sibling | Margaret DE FURNEAUX (1300 - 1349) |
| Sibling | Jone Johanna De FURNEAUX (1300 - ) |
| Sibling | Lady Margaret FURNEAUX (1302 - 1365) |
| Sibling | John DE FURNEAUX (1304 - 1336) |