| Father | Sir John St John Baron of Beauchamp of Bledso (1450 - 1525) |
| Mother | Sybil Verch Morgan (1453 - 1529) |
| Sibling | Lady Alice St. John Baroness (1485 - 1552) |
| Sibling | Margaret St. John (1486 - 1562) |
| Sibling | Catherine Eva Saint John (1475 - 1553) |
| Sibling | Elizabeth St John (1488 - ) |
| Sibling | Sybil St John (1490 - ) |
| Sibling | John St. John VI (1498 - 1562) |
| Sibling | Sir Oliver Saint John (1498 - ) |
| Sibling | Katherine John (1502 - 1551) |
| Sibling | Catherine St John (1478 - ) |
| Sibling | Alice St. John (1488 - 1515) |
| Sibling | Sibyll De St. John (1491 - ) |
| Sibling | Alexander St John (1499 - 1551) |
| Sibling | Henry St John ( - 1598) |
| Sibling | Catherine Saint John ( - ) |