Across four studies, we examined whether certain personality traits cue prejudice and serve as identity threat cues. Stigmatized group members may be vigilant to personality cues that signal prejudice. In Study 1 (N = 76), perceivers selected traits and behaviors associated with disagreeableness and closedness to experience as indicators of prejudice. In Studies 2-4, perceivers with stigmatized identities (Total N = 907) learned about a target person who was depicted as disagreeable or agreeable (Studies 2 and 3) and as disagreeable or another trait matched on perceived negativity (i.e., low in conscientiousness, Study 4). Participants perceived the disagreeable target as more discriminatory and hierarchy-endorsing (Studies 2-4), more morally disengaged (Study 3), and more likely to discriminate against stigmatized identity groups (Studies 2 and 4) than the agreeable or low conscientious targets. The relationship between target disagreeableness and perceived discrimination was partially explained by higher perceived hierarchy endorsing beliefs (Studies 2-4) and perceived moral disengagement (Study 3). This research finds that perceivers with stigmatized identities utilize target disagreeableness as a cue of identity threat, inferring that disagreeable people are more likely to be discriminatory, prejudicial, and hierarchy-endorsing than agreeable and low conscientious people.