We investigate trust relationships between senior business executives and their overseas partners. Drawing on the similarity-attraction paradigm, social categorization theory, and the distinction between cognition- and affect-based trust, we argue that executives trust their overseas partners differently, depending on the partners' cultural ethnicity. In a field survey of 108 Chinese senior executives, we found that these executives have higher affect-based trust in overseas partners of the same cultural ethnicity as themselves; cognition-based trust is associated with affect-based trust differently when overseas partners are of the same or different cultural ethnicity. We also examine the role of relative firm size and age in shaping intra- and intercultural trust. Relative firm size has a stronger negative effect on executives' cognition-based trust if their partners are of a different cultural ethnicity. Although firm age does not have a negative effect on executives' affect-based trust as hypothesized, we found firm age to be positively associated with affect-based trust for partners of the same cultural ethnicity. We discuss theoretical and practical implications of this pattern of inter- and intra-cultural trust on international business and networking (guanxi) dynamics in China.