Tiberius Julius Cotys III

Cotys III or Kotys III (, Tiberios Iulios Kotys Philocaesar Philoromaios Eusebes; – 234) was a Roman client king of the Bosporan Kingdom.

Like many of the other late Bosporan kings, Cotys III is known mainly from coinage, meaning that the historical events of his reign are largely unknown. His coins are known from the period 228–234. He is known from an inscription to have been the son of his predecessor, Rhescuporis III.

Cotys III's coinage overlaps with the coins of Sauromates III, perhaps his brother, and Rhescuporis IV. They might thus have been co-rulers with him. His relationship to later kings is unknown, though it has been suggested that he was the father of Ininthimeus.