John III, Bishop of Nyitra

John (Hungarian: János; died between 9 and 18 March 1328) was a Hungarian prelate in the first half of the 14th century, who served as Bishop of Nyitra (present-day Nitra, Slovakia) at least from 1302 until his death. He belonged to the earliest partisans of Charles I of Hungary and his dynasty. During his reign, which roughly coincided with the era of feudal anarchy, the diocese of Nyitra was constantly harassed and plundered by the troops of the powerful and greedy oligarch Matthew Csák.