Abstract: Disclosed are rotary sprinklers having a turret mounted drive system. In one aspect, the complete drive mechanism, including all components thereof, is positioned in the rotary turret portion of the rotary sprinkler. In another aspect, the turret mounted drive system includes a main drive element, such as a turbine, paddle wheel, or the like, positioned adjacent a flow passage or nozzle outlet and oriented to be driven from a fluid flow projected from the sprinkler. In yet another aspect, the turret mounted drive system also has associated gearing assemblies, which may include appropriate gear reduction modules, also mounted within the turret, but outside of the fluid flow path.