| Father | Gilbert De Clare 5th Earl of Gloucester (1182 - 1230) |
| Mother | Isabel Marshall (1200 - 1240) |
| Sibling | Earl Richard De Clare Iv, of Gloucester (1222 - 1262) |
| Sibling | Amica De Clare (1220 - 1285) |
| Sibling | Susan De Clare (1224 - ) |
| Sibling | Sir William De Clare (1228 - 1258) |
| Sibling | Susan De de Clare (1217 - ) |
| Sibling | Isabella Lady of Hertford And Gloucester De Clare (1226 - 1264) |
| Sibling | Agnes De Clare (1229 - 1261) |
| Sibling | Gilbert De Clare (1226 - 1241) |
| Sibling | Gilbert De Clare (1229 - 1241) |
| Sibling | Isobel De Clare (1217 - ) |
| Sibling | Walter De Clare ( - ) |
| Sibling | Thomas De Clare (1224 - ) |
| Sibling | Avicia De Clare (1220 - 1284) |
| Sibling | Adeliz De Clare (1228 - ) |
| Sibling | Joan De Clare (1210 - ) |