We have investigated the morphology and packing manner of graft copolymers consisting of rigid-rod-like poly(gamma-benzyl L-glutamate) (PBLG) main chains and grafted diblock copolymers of amorphous poly(propylene glycol) (PPG) and crystalline poly(ethylene glycol) (PEG). The results of differential scanning calorimetry and wide-angle X-ray scattering measurements for graft copolymers with higher side-chain volume fractions suggest that the rodlike main chains and crystallized PEG chains exist in segregated domains. Small-angle X-ray scattering profiles for these samples show diffraction intensity maxima accompanied by higher order peaks, the positions of which suggest the formation of an ordered layered structure. From these observations, the graft copolymers are estimated to form repeated layered structure consisting of segregated PBLG, PPG, and PEG layers. A proposed model for molecular packing of the graft copolymers is consistent with the experimental observation that the repeating distance for the layered structure decreases with an increase in the volume fraction of side chains.