This dissertation aims to understand how global health advocacy networks seek issue attention. It focuses particularly on how network actors use communication campaigns to exercise power for that aim. This study is guided by Shiffman and Smith’s framework on the determinants of health policy prioritisation (2007). The framework proposes actor-power, ideas, political context, and issue characteristics as interdependent categories to analyse how and why certain health initiatives gather attention, and why others fail to gain priority. To expand on Schiffman and Smith’s framework, the thesis applies social theories concerned with competition and conflict to examine the role of network-led campaigns. Processes of power and competition among network actors offer rich scope for analysis. These are examined in this study through the integration of complementary theories from Sabatier and Bourdieu. This study found that campaigns are both a driver and product of actor-power. Campaigns unite heterogeneous actors through the production of shared messages and normative claims; they promote visibility for network messages and goals; and they contribute to network growth and replication by linking actors across different scales, from local to global, and vice versa. Therefore, greater attention to how network actors compete, negotiate and communicate through campaigns, and to how they acquire and use network capital at multiple scales, will enrich any future use of the Shiffman and Smith framework. Qualitative methods in this thesis included historical process-tracing of network and campaign development; document analysis; and in-depth interviews with network actors to reveal patterns of social relations. This was triangulated by longitudinal participant-observation methods. Once revealed and examined, how network power is legitimated and held to account is an important question for the future study of the political determinants of global health priorities.