A rotor of a gas turbine, having two adjacent rotor disks having a plurality of blade-holding grooves for receiving rotor blades, distributed around the periphery thereof, and having an axially extending peripheral ring projection radially beneath the blade-holding grooves. A peripheral rotor component is fixed to the ring projections, between the rotor disks. In order to protect the periphery, the rotor disk or the rotor component includes at least two recesses arranged on the periphery in a distributed manner, in each of which engaging shoulders of the rotor component or the rotor disk engage.