The structure of silica glass has been studied by comparing calculated x-ray scattering patterns of structural models with experimental scattering patterns. The structural models chosen are of random arrangements of silica tetrahedra containing preferred intertetrahedral configurations resulting in a degree of order on a local scale in the otherwise random network. Examination of the derivation of the radial distribution function from x-ray scattering data has shown that the occurrence of such local configuration is not excluded. In the structural model chosen the tetrahedra link together preferentially in ways similar to the tetrahedral arrangements in the crystal forms cristobalite and tridymite so that non-planar rings occur consisting of mainly 5, 6 and 7 tetrahedra. In calculating the scattering patterns, diffraction ripples arise from the shape of the model and consideration is given to their removal. The calculated x-ray scattering patterns are found to be in agreement with experiment; and best agreement is obtained when the Si–O–Si angle is about 150° and when the model contains a proportion of 7-membered non-planar rings of tetrahedra rather than non-planar rings of only 5 and 6 tetrahedra. Experimental and theoretical estimates of the sensitivity of the x-ray scattering patterns to structural detail are discussed.