Undocumented immigrants are generally assumed to exhibit clear signs of their so-called outsider status. In the absence of such signs, however, how is the “illegal immigrant” made legible or policed? How might migrants negotiate their statuses as objects of state surveillance by exploiting their similarities or affinities with those who seek them out? Spectres of Affinity explores these issues in the east Malaysian state of Sabah, a scene of some of the largest clandestine cross-border flows in the world, and a place where migrants are widely assumed to look, talk, and otherwise behave like locals. In Sabah, the ability of outsiders to pass as insiders has long animated public anxieties about the boundaries of citizenship, ethnicity, race, religion, labour, and language. Against this backdrop of social indeterminacy and political uncertainty, migrants and Malaysians are now jointly evaluating and adjudicating the ways they are sama, tapi berbeza – “the same, but different” – to sometimes devastating effect. In exploring the social life of comparison in the shadow of a notoriously porous Southeast Asian border, Spectres of Affinity calls for renewed attention to comparison not merely as a rarefied social scientific method or mode of inquiry, but as part of people’s everyday equipment for living in increasingly uncertain and unsettling times.