In summer 2015, a social movement of support emerged as thousands of people crossed Europe. Participants in this translocal movement and the social worlds that wove through it included anarchists expanding upon “NoBorder” networks, volunteers working with grassroots NGOs, refugees fleeing political persecution, and victims of non-targeted violence seeking sanctuary. In Athens, Greece, these stakeholders came together in a networked field of initiatives that crossed vast divides of political ideology and material capacity (and whose activities were sharply curtailed between autumn 2019 and winter 2020). Many of the people offering aid during this time understood their actions through the rubric of “refugee solidarity.” This dissertation questions what refugee solidarity meant for those who aspired to it—and also, what it meant for some people who didn’t necessarily aspire to it. To facilitate this investigation, I disarticulate two sides of solidarity that emerged in Athens refugee solidarity worlds. There’s solidarity-as, the notion of community and belonging that transcends difference to form a solid “we” of political identity. And there’s solidarity-with, which carries associations of allyhood, accompaniment, and otherness: It indexes difference in order to foment liberatory action. Anchored by this two-part understanding of solidarity, in the first section of the dissertation I trace layers of local history around solidarity that underlay the 2015-19 movement in Athens. In the second section, I use a zoomed-out, data-driven archival methodology of network study to understand the mixed social worlds that emerged around the refugee solidarity movement in 2015-19. Finally, in the third section I engage personal ethnographic anecdotes to understand social relations around the label “refugee” inside Athens refugee solidarity worlds. Overall, I show how Athens refugee solidarity worlds re-affirmed the hierarchies imposed by the label “refugee” even while fomenting transformative potentials to move beyond that label, and I argue that solidarity always depends upon a careful negotiation of the sameness and difference inherent to allyhood and community.