A unitary interstage sealing ring for bridging and sealing the space between the blade shanks of adjacent turbine rotors in a multi-stage turbine. The sealing ring serves to confine relatively cool air conveyed to the turbine so the cooling air flows into the turbine blades for maintaining the blades at a desired temperature. The sealing ring includes a disk-shaped body member that includes a pair of axially-spaced, radially-extending arms that terminate in respective seal teeth for engagement with a stationary annular sealing member. Each of the radial arms includes an outwardly-extending axial arm that terminates in a disk engagement member for sealing engagement with the face of an adjacent turbine disk to confine cooling air within the space between the adjacent turbine disks. Additionally, one of the disk engagement members includes at least one, projection that contacts a respective turbine rotor to limit relative rotation between the sealing ring and the turbine.