Five experiments (N = 2,251) and a meta-analysis examine how group labels shape Americans’ levels of prejudice, behavioral intentions, and policy preferences toward immigrants living in the US without authorization. These studies extend research documenting how the perceived negativity of group labels (e.g., those describing gay people) affects people’s downstream attitudes. To this end, Study 1 examines the perceived negativity of the five most commonly used labels to describe unauthorized immigrants. Study 2 found that relatively negative (vs. neutral) labels (e.g., illegal aliens vs. noncitizens) engendered more prejudice, punitive behavioral intentions, and greater support for punitive policies. Study 3 replicates these effects and examines the role of familiarity. People who personally knew members of the group were more positive towards them overall, but were nevertheless susceptible to the labels’ influence. Studies 4 and 5 provide additional replications and explore prejudice as a mediator of behavioral intentions and policy preferences.