In the twenty years since the adoption of United Nations Security Council resolution 1325 on "women, peace and security" (in 2000), civil society organisations have continued to shape the agenda's development and work towards its implementation, although geographical and other disparities in recognition, access, and authority over the agenda exist. In this research, we explore the online interactions among civil society organisations working on policy and practice related to the Women, Peace and Security (WPS) agenda. Informed by a postcolonial theoretical framework, and using social network analysis, we analyse data from the Twitter and Facebook accounts of a WPS social network, seeded by social media pages of 21 organisations. Our data suggest that a small group of organisations based in the global North have disproportionate visibility in online activities related to the WPS agenda, and that this has implications for issues of diversity and representation in the network.