| John III, Count of Nassau-Beilstein | |
| Noble Family: | House of Nassau |
| Father: | John II, Count of Nassau-Beilstein |
| Mother: | Maria of Solms-Braunfels |
| Spouse: | Anna of Nassau-Weilburg |
| Birth Date: | 1490 |
John III, Count of Nassau-Beilstein (1490 - 11 December 1561) was a son of John II and his wife Maria of Solms-Braunfels.[1]
In 1513, he succeeded his father as Count of Nassau-Beilstein. In 1523, he married Anna (1505–1564), a daughter of Louis I (1473–1523) of Nassau-Weilburg and Margaret of Nassau-Wiesbaden (1487–1548).
He died on 11 December 1561. As he had no male heir, Nassau-Beilstein fell back to Nassau-Dillenburg. He may have had a son, Jonas/Hans, but more documentation is needed to confirm. It is unclear why this son, if he existed, did not inherit his father's title.