As the notion of a “right to health” gains influence, it is increasingly deployed in ways that are diverse, contextually variable, and at times logically inconsistent. Drawing on extended fieldwork at an Israeli human rights organization that advocates for “illegal” migrants and other vulnerable groups, this article contends that medical anthropologists cannot simply rally behind this right. Instead, we must take it as an object of ethnographic analysis and explore how it is invoked, debated, and resisted in specific contexts. Critical ethnographies of right to health discourse and practice can enlighten us, and help us enlighten scholars in other fields, to the complexity, messiness, and “mushiness” (Sen 2009) of this right, especially in the context of advocacy on unauthorized im/migrants’ behalf. It can also deepen understanding of the complicated and sometimes tense relationships among human rights, humanitarianism, and other contemporary idioms of social justice mobilization, especially in the health domain.