We present a combined core-level spectroscopy and low-energy electron diffraction study of the evolution of thin CuI layers on graphene/Ni(111) during annealing. It has been found that the annealing of the CuI/graphene/Ni(111) system up to 160°C results in the formation of an ordered CuI overlayer with a (√3 × √3) R30°structure on top of the graphene surface. At annealing temperatures of about 180°C or higher, the CuI overlayer decomposes with a simultaneous intercalation of Cu and I atoms underneath the graphene monolayer on Ni(111). Nearly complete intercalation of graphene by Cu and I atoms can be achieved by deposition of about 20 Å of CuI, followed by annealing at 200°C. The intercalated graphene layer is p-doped due to interfacial iodine atoms.