In this paper, influence of modified strain gradient theory (MSGT) on buckling, free and forced vibration characteristics of the composite cylindrical nanoshell reinforced with graphene nanoplatelet (GPL) in thermal environment is investigated. The material properties of piece-wise functionally graded graphene-reinforced composites GPLRC are assumed to be graded in the thickness direction of a cylindrical nanoshell and are estimated through a nanomechanical model. The results show that GPL distribution pattern, three length scale parameters, number of layers and GPL weight function have important role on resonance frequencies, buckling load, relative frequency and dynamic deflections of the GPLRC cylindrical nanoshell.