The treatment and analysis of small‐angle X‐ray scattering data are reviewed with specific concern for the glass science. The studies detail the characterization of the submicroscopic structure existing in terms of two‐phase particulate systems, multiphase particle systems, non‐particulate systems, including those of fractal surfaces, and the application of small‐angle X‐ray scattering to the examination of the intermediate‐range order of glasses. The methods developed are illustrated by small‐angle X‐ray scattering and anomalous small‐angle X‐ray scattering results obtained from optical filter glass, glass produced by the sol–gel technique, optical colorless glass inclining to opalescence, porous glass and single‐phase phosphate glass.