Phosphatidylcholine vesicles in the diameter range, 40 to 115 nm scatter light as isotropic hollow spheres within the Rayleigh-Gans-Debye (RGD) approximation. A more complex model (i.e., the exact or Lorenz-Mic theory) is not required for accurate interpretation of the static light scattering data. The scattered light intensity measurements also allow for the determination of the vesicle weight-average molecular weight through a Zimm plot analysis. This information, in combination with the vesicle size as determined within the RGD approximation, indicates that the vesicle wall thickness is close to 3.6 nm as previously determined by X-ray diffraction methods. Thus, static light scattering techniques may provide excellent estimates of surfactant vesicle wall thicknesses.