Vibrational properties of water molecules retained in the interlayer space of graphene oxide were studied by combining inelastic neutron scattering spectroscopy with density functional theory calculations. The credibility of Lerf-Klinowski model in the description of the amplitude weighted vibrational density of states has been successfully examined. The solid-state plane-wave DFT computations have delivered satisfying qualitative interpretation of the INS spectrum, which was found to be mainly driven by the vibrational dynamics of the retained water. (C) 2014 Elsevier B.V. All rights reserved.