In Irish mythology, Naoise (also spelled Noise, Noisiu) was the nephew of King Conchobar of Ulster, and a son of Usnech (or Uisliu ), in the Ulster Cycle.

When Deirdre was born, Cathbad the druid prophesied that she'd be beautiful, but that kings and lords would go to war over her. Conchobar decided to have her brought up in seclusion, and when she was old enough, he'd marry her. However she met, fell in love with, and eloped with Naoise, a handsome young warrior, hunter and singer, accompanied by his two brothers. They fled to Scotland, but wherever they went the local king would try and kill Naoise and his brothers so he could have Deirdre. Eventually they ended up on a remote island, where Conchobar tracked them down and sent Fergus mac Róich to them with a message of safe conduct home. But on the way back to Emain Macha Fergus was waylaid and Conchobar had Naoise and his brothers murdered so he could forcibly marry Deirdre. Fergus was outraged by this betrayal of his word, and went into exile in Connacht. Deirdre committed suicide, or in later versions of the story, died of grief.