AbstractResearch on residential mobility is burgeoning; however, only a few studies have examined this topic in the context of impression formation. In Study 1, we first examined the hypothesis that high residential mobility increases sensitivity to friendliness, whereas low residential mobility increases sensitivity to hostility. In the word completion task, no effects of residential mobility were observed; however, in the impression formation task, participants with high residential mobility perceived friendly new acquaintances with higher amicability than those with low residential mobility (Studies 1a and 1c). Meanwhile, no effect was observed with the hostile new acquaintances (Study 1b). The results suggest that the effects of residential mobility, with a focus on friendliness and hostility, may be highly context dependent. Study 2 partially confirmed this idea, showing that participants with low residential mobility perceived hostile old acquaintances as less friendly than those with high residential mobility, and there was no effect of residential mobility in the case of friendly old acquaintances (Study 3). The role of residential mobility on impression formation was discussed.