We present theoretical results for intensity-dependent above-threshold ionization (ATI) spectra from oriented OCS molecules probed by intense femtosecond laser pulses with wavelengths of 800 and 400 nm. The calculations were performed using the time-dependent Schrödinger equation within the single-active-electron approximation and including multielectron polarization effects. The results capture some of the experimental findings (Yu et al 2017 J. Phys. B: At. Mol. Opt. Phys. 50 235602), in particular when considering the sensitivity of the ATI spectra on the molecular orientation. We identify characteristic features in the ATI spectra which correspond to resonant multiphoton ionization via highly-excited Rydberg states are captured by the theory.