The aim of this thesis was to understand the role of epistemic communities in the global response to Severe Acute Respiratory Syndrome (SARS), through the theoretical lens of Social Constructivism, in order to explain the extent to which ideational factors and normative power constructed through them contributed to the shaping of Global Health Governance (GHG) surrounding infectious disease outbreaks. The methodology of this thesis combined key informants interviews with archival document‐based research. Archival research consisted of gathering and reviewing government documents, publications of intergovernmental organizations, media reports, press briefings, and policy papers. Discourse analysis was employed to systematically examine the wide range of data gathered. The thesis explored how different discourses have driven the changes in public health reasoning and practice, in the form of prioritisation of certain actions in the global response to SARS at various points in time. In order to show the ideational shifts over time, the SARS story was divided into three key phases in terms of the progress of the outbreak. This thesis finds that the global response to the SARS outbreak over three phases was shaped by contestation among various discourses, which framed the perceived priority issues and policy responses pursued. These ideas did not simply arise as governing norms, but ideational success occurred as a result of collective advancement by actors who were coalesced around particular policy ideas. The thesis provided an account of the interplay between policy ideas and key actors, in the form of epistemic communities, and how epistemic communities served as key sources of advice to policy making during the SARS outbreak. The thesis demonstrates that in many ways, the GHG of SARS mirrored, the GHG of other global health issues in terms of framing of issues and the actors in the formation of and justification for interests in global health. By illustrating the origins and significance of the multiplicity of ideas shaping collective action on SARS, this thesis underscores that governance response in terms of policy outcomes is the product of reconciling health with a plethora of competing priorities, and political economic goals via social construction of reality. The thesis considered the implications of the findings for conceptual understanding of GHG of infectious diseases, and for strengthening policies and practices to address the global infectious disease outbreaks.