The first three-dimensional potential energy surface (PES) of the Ar-OCS complex is developed at the coupled cluster single and double with noniterative treatment of triple excitations [CCSD(T)] level with a large basis set plus midpoint bond functions. Two vibrationally adiabatic potentials at both the ground and the first vibrational v(3) excited states are generated by averaging the three-dimensional potential over the Q(3) coordinate. The predicted infrared spectra are in excellent agreement with the available experimental data, which again testifies the accuracy of the new potentials. (C) 2013 Elsevier B.V. All rights reserved.