Multicultural experiences – such as living, traveling, or working abroad – can have many psychological benefits, including decreasing intergroup bias. However, unlike the intergroup contact literature, research on multicultural experiences has yet to examine whether the valence of these experiences may moderate such outcomes. So, could multicultural experiences actually increase intergroup bias? Five studies reveal that multicultural experiences increase (rather than decrease) intergroup bias when those experiences are negative (rather than positive). Across multiple methods (recall priming; virtual reality simulation), and experiences across multiple countries, negative multicultural experiences increased intergroup bias (stereotyping; prejudice) – both to groups associated, and stigmatized groups not associated, with the specific multicultural experience. This increased bias did not extend to ingroup members or non-human targets. The impact of negative multicultural experiences on increased bias was mediated by changes in intergroup ideologies/worldviews – specifically social dominance orientation. These findings reveal how multicultural experiences can be a double-edged sword in our increasingly globalized world.