This paper documents the production of a compendium of modelling and simulation (M&S) tools useful for decision support to organizations engaged in domestic defence and security operations. The compendium was created on GCPEDIA, a wiki application accessible to all federal government departments and agencies in Canada. It includes tools for predicting the consequences of natural and man-made disasters, planning major event security, assessing infrastructure criticality, planning surveillance missions, and analyzing other issues relevant to domestic operations. Given the wide accessibility of the compendium within the Government of Canada, a large community of practice can use, update, and expand on the information collected