Networks have been argued to be essential in the field of emergency management for the design of policies and delivery of programs. Networks have been theorized to be capable of becoming the dominant governance structure in sectors of society. However, how networks develop and why they are rising in prominence is a contested issue. Moreover, the increasing prominence of networks in governance has complex implications that have yet to be fully explored. This thesis uses process tracing to knit together the analysis of provincial emergency response plans, after action reports, and semi-structured interviews with twenty-three emergency management professionals in order to make inferences on the development of characteristics of emergency management networks and governance in the Province of Ontario between the years of 1991 and 2018. This thesis contributes to an understanding of how and why emergency management networks and governance in the province have developed during this time.