Dissymmetric and symmetric anionic gemini surfactants, N-alkyl-N’-alkyl-N,N’dipropanesulfonylethylenediamine (C_mC_nSul, where m and n represent alkyl chain lengths of m-n = 4-16, 6-14, 8-12, 10-10, and 12-12), were synthesized by two- or three-step reactions. Their physicochemical properties were characterized by equilibrium surface tension measurements, steady-state fluorescence spectroscopy of pyrene, and dynamic light scattering. The critical micelle concentration (CMC) of the dissymmetric surfactants C₄C₁₆Sul, C₆C₁₄Sul, and C₈C₁₂Sul was slightly lower than that of the symmetric surfactant C₁₀C₁₀Sul. The occupied area per molecule (A) of C₈C₁₂Sul was smaller than that of C₁₀C₁₀Sul, indicating that C₈C₁₂Sul has a high surface activity. However, the increase in the degree of dissymmetry from C₈C₁₂Sul to C₆C₁₄Sul and then to C₄C₁₆Sul resulted in high surface tension and large A. Based on the surface tension, the standard free energies of micellization (∆G°_mic) and adsorption (∆G°_ads), the efficiency of surface adsorption (pC₂₀), and the effectiveness of surface adsorption (CMC/C₂₀) were obtained. These parameters suggested that C₈C₁₂Sul formed micelles more readily than the other surfactants. The properties determined from the surface tension indicated that C₈C₁₂Sul’s ability is intermediate between those of C₁₀C₁₀Sul and C₁₂C₁₂Sul. The pyrene fluorescence and dynamic light scattering results revealed that the micelle size depends on the longer of the two alkyl chains in dissymmetric surfactants.