Reactions of O-18(2) with self-assembled monolayer (SAM) films of 1-dodecanethiol, 1-octadecanethiol, 1-butanethiol, and benzyl mercaptan chemisorbed on gold were studied by the electron stimulated desorption (ESD) of anionic fragments over the incident electron and (OH-)-O-18 desorption signals increase with electron fluence and that in the energy range 2-20 eV. Dosing the SAMs with O-18(2) at 50 K results in the ESD of O-18(-) and (OH-)-O-18. Electron irradiation of samples prior to O-18(2) deposition demonstrates that intensity of subsequent O-18(-) and (OH-)-O-18 desorption signals increase with electron fluence and that in the absence of electron preirradiation, no O-18(-) and (OH-)-O-18 ESD signals are observed, since oxygen is unable to bind to the SAMs. A minimum, incident electron energy of 6-7 eV is required to initiate the binding of O-18(2) to the SAMs. O-2 binding is proposed to proceed by the formation of CHx-1 center dot radicals via resonant dissociative electron attachment and nonresonant C-H dissociation processes. The weaker signals of O-18(-) and (OH-)-O-18 from short-chain SAMs are related to the latter's resistance to electron-induced damage, due to the charge-image dipole quenching and electron delocalization. Comparison between the present results and those for DNA oligonucleotides self-assembled on Au (Mirsaleh-Kohan, N. et al. J. Chem. Phys. 2012, 136, 235104) indicates that the oxygen binding mechanism is common to both systems.