The hostile and anxious responses of young adults to an immigrant (vs. native-born) stranger were examined as a function of participants’ self-perceived power. In Studies 1 and 2, individuals with low perceived social power (males, in particular) showed high anxiety toward an “outsider” but more so if that individual was an immigrant (and thus posed an ambiguous threat to their position in the hierarchy). In Study 3, young adult males competed on a reaction time test with an immigrant or native-born rival. With immigrant rivals, males with low perceived social power showed relatively high aggression toward an immigrant rival and derogation of the rival’s formidability; however, they showed a more deferential pattern with native-born rivals.