Thousands of Central American women have been displaced from their countries of origin by violence. While the violence committed against them is often portrayed as isolated acts of aggression, women’s suffering is also produced and perpetuated by humanitarian interventions that immobilize women in dangerous transit zones. Interventions are then justified by institutional logics that juxtapose women’s vulnerability against the threat of their own mobility. This article draws on 14 months of ethnographic fieldwork along the southern Mexico border among migrant women who sought out humanitarian assistance following violent encounters. Central to my argument is the concept of mobility imaginaries, or widely shared social assumptions about how mobility should and can be accessed, by whom, and under what circumstances. Through this framework, I show how gendered mobility biases that underlie institutional logics compound other forms of institutional inequality, which often serves to reproduce, rather than mitigate, root causes of gender‐based vulnerability.