Reaction mechanisms are formulated for the atmospheric photooxidation of the organosulfur compounds, dimethyl sulfide, CH3SCH3, methanethiol, CH3SH, and diethyl sulfide, C2H3SC2H5. Predictions of the mechanisms are compared with available data on laboratory photooxidations of these three species to identify critical uncertainties in chemical pathways and reaction rate constants. The sensitivity of product yields to these uncertainties is investigated.