John III, Count of Nassau Dillenburg

John III, Count of Nassau-Dillenburg (died either in 1429/1430 or 1433) was Count of Nassau-Dillenburg in Siegen and Dillenburg and son of Count John I, Count of Nassau-Dillenburg and Margareta of the Marck.

After the death of Count John I in 1416 his lands were not divided, but instead overseen by all four of his surviving sons Adolf, John II, Engelbert I and John III. John III was provost in Munster, and he never married.