The quasi-reversible one-electron reduction of oxygen in dimethylsulfoxide is reported for a range of electrode materials (C, Pt, Pd, and Au) and temperatures (293–343 K). Modelling was undertaken using Butler-Volmer and symmetric Marcus-Hush methods, with the former found to provide more reproducible results for this system, in agreement with previous reports of quasi-reversible systems. The reorganisation energy for the reaction was found to be ca. 1.0 eV, and the reaction confirmed to be predominantly outer-sphere. The observed standard electrochemical rate constant (k 0) is ca. 5.7 times faster for C electrodes than Pt, despite having a lower electronic density of states.