This paper engages in debates about the spatiality of social movements which have argued that examining politics purely through territorial or relational understandings of space does not adequately grasp the ways in which social movements undertake their activities. The paper argues that a possible route through this debate lies in the concept of assemblage, which has recently been deployed in geography in order to understand the emergence and practice of social organisation and activity. The paper develops these ideas through an empirical discussion of the practices that help to maintain a particular social movement organisation – a Tibet Support Group (TSG). Through ethnographic engagement with a particular TSG, the paper argues that through the quotidian activities like delivering the mail we can understand how sociospatial practices within an organisation display both territorial and relational elements at the same time. This develops an account that advances knowledge of the spatiality of political action, and with it the ability of assemblage to understand organisational practices, but also develops theoretical insights into TSGs as a particular type of organisation.