Changes in the positions of the sulfonate and the methyl groups on the aromatic ring of alkylxylene-sulfonate were found to produce a marked effect on the micellization and adsorption at the solid/liquid interface of alkylxylenesulfonates. Fluorescence spectroscopy was used to probe the microstructure of the micelles and hemimicelles of the surfactants. The studies showed the p-xylenesulfonate micelles to be less polar and the p-xylenesulfoante micelles and hemimicelles to have higher aggregation number than the m-xylenesulfonate micelles and hemimicelles, respectively. Based on results obtained, steric constraint to the packing of these molecules in the aggregates was determined to be the main reason for the differences in the micellization and hemimicellization of the surfactants.