--- - |2 Abstract This study examined whether implicit theories of shyness differed between American and Chinese children and how this difference helped explain cultural variations in stereotypical views about shy children and relationship with shy peers. We found that regardless of cultural group, children's implicit theories of shyness were not related to their own shyness, but were associated with stereotypical views about shy children (positively) and relationship with shy peers (negatively). American children reported stronger entity theories of shyness, i.e., they were more likely to view shyness as a stable and immutable trait than Chinese children, which partly explained why they had worse relationships with shy peers. These findings highlight the important roles implicit theories may play in understanding cultural similarities and differences in interpersonal perception and relationship. - European Journal of Social Psychology, EarlyView.