Cináed mac Conaing (died 851) was King of Knowth in the medieval Irish province of Mide, succeeding his father Conaing mac Flainn in 849.

Cináed's family belonged to the Knowth, or Uí Chonaing, branch of the Síl nÁedo Sláine, part of the southern branch of the dominant Uí Néill kin