| Father | John Fitzwilliam (1328 - 1385) |
| Mother | Elizabeth Clinton (1328 - 1419) |
| Sibling | Sir William FitzWilliam of Emley (1340 - 1428) |
| Sibling | Mary Fitzwilliam (1347 - ) |
| Sibling | Joan FitzWilliam (1355 - ) |
| Sibling | Edmund Fitzwilliam Constable of Conisbrough Castle (1356 - 1430) |
| Sibling | Anne FitzWilliam (1358 - ) |
| Sibling | John FitzWilliam (1360 - ) |
| Sibling | Richard FitzWilliam (1362 - 1399) |
| Sibling | Jane FitzWilliam (1365 - 1459) |
| Sibling | Margaret FitzWilliam (1366 - ) |
| Sibling | Thomas FitzWilliam (1366 - ) |
| Sibling | Son Fitzwilliam (1372 - ) |
| Sibling | Geoffrey Fitzwilliam (1382 - 1439) |
| Sibling | Jane Fitzwilliam ( - ) |