| Father | Oliver De St. John (1400 - 1440) |
| Mother | Margaret Beauchamp (1410 - 1468) |
| Sibling | Sir John St. John I (1426 - 1489) |
| Sibling | Elizabeth St. John (1439 - 1494) |
| Sibling | Margaret St. John (1436 - 1492) |
| Sibling | Edith St. John (1430 - ) |
| Sibling | Agnes St. John (1438 - 1494) |
| Sibling | Mary St John (1434 - 1492) |
| Sibling | Margaret St John (1448 - ) |
| Sibling | Edith St. John (1442 - 1486) |
| Sibling | Oliver St. John of Lydiard Tregoze, Wiltshire (1430 - 1497) |
| Sibling | Elizabeth St. John (1448 - 1494) |
| Sibling | Sir Oliver de St. John (1423 - ) |
| Sibling | Elizabeth St John (1432 - 1494) |
| Sibling | Edith John (1430 - 1466) |