Nycteus was a king of Thebes and the eldest son of Chthonius. He married Polyxo who bore him Antiope and Callisto. His name appears to mean 'of the night', from nyx, nydos, 'night'.

There seems to have been nothing noticeably 'black' or evil about his life, although Antiope fled from her father when she became pregnant by Zeus and either his anger or his grief at her departure could be regarded as 'black'. (According to one account, his grief was so great that he died of a broken heart.)