Inelastic neutron scattering spectra of silicalite, Na-ZSM-5, zeolites X, and Y are measured and compared with the spectra obtained by molecular dynamics simulations of the zeolitic frameworks. Comparison of the spectra shows a good general agreement of the experimental and modeling results, indicating that a generalized force field correctly describes the dynamics of the frameworks. Some discrepancies are observed. They are assigned to defects in the samples and to the neglect of electrostatic interactions in the force field model.