Two series of amphiphilic derivatives of lactose have been synthesized. Tensiometric investigations of the critical micellar concentration (CMC) and the area per molecule at interface (calculated by the Gibbs equation) of aqueous solutions were performed. The values measured depend on the number of methylene groups of the alkyl spacer n and that of the side chain m as well as on the ionic strength and temperature. The results show a behavior closely related to that of gemini surfactants: (1) self-assembly phenomena occur at concentrations below 1 mM, (2) at constant n log CMC increases linearly with higher m, and (3) the influence of the temperature on the aggregation phenomenon is comparable.