Henry I, Count of Nassau-Beilstein (1307–1388) was a son of Henry I of Nassau-Siegen and his wife, Adelaide of Heinsberg-Blankenberg. His parents had initially destined him for an ecclesiastical career. However, he later married Meyna of Westerburg and after his father's death became the first count of Nassau-Beilstein.

Henry and Meyna had three children:

• Henry II, his successor
• Reinhard (d. 1412)
• Adelaide, married Hartmuth of Cronberg.