Periodic Mesoporous Silicas (PMS) are one of the prime examples of templated porous materials – there is a clear connection between the porous network structure and the supramolecular assemblies formed by surfactant templates. This opens the door for a high degree of control over the material properties by tuning the synthesis conditions, and has led to their application in a wide range of fields, from gas separation and catalysis to drug delivery. However, such control has not yet come to full fruition, largely because a detailed understanding of the synthesis mechanism of these materials remains elusive. In this context, molecular modelling studies of the self-assembly of silica/surfactant mesophases have arisen at the turn of the century. In this paper, we present a comprehensive review of simulation studies devoted to the synthesis of PMS materials and their hybrid organic-inorganic counterparts. As those studies span a wide range of time and length scales, a holistic view of the field affords some interesting new insight into the synthesis mechanisms. We expect simulation studies of this complex but fascinating topic to increase significantly as computer architectures become increasingly powerful, and we present our view to the future of this field of research.