Does mixed-ethnicity marriage cause a decrease in one’s level of ethnic identification? Using shared reality theory (Hardin & Conley, 2000; Hardin & Higgins, 1996), which posits that interpersonal relationships are built upon commonly held attitudes and beliefs, it was predicted that positive relationships with same-ethnicity others will elicit high ethnic identification but that positive relationships with different-ethnicity others will elicit lower ethnic identification. In this study, 112 Asian American women (66 from same-ethnicity marriages, 46 from mixed-ethnicity marriages) were instructed to think of the positive aspects of either their relationship with their spouse or their relationship with their mother. Women in mixed-ethnicity marriages thinking about their different-ethnicity spouse reported lower ethnic identification on the Multigroup Ethnic Identity Measure (Phinney, 1992), compared to women in mixed-ethnicity marriages thinking about their mother and to women in same-ethnicity marriages thinking about their mother or their spouse. Greater shared understanding of ethnicity with mother accounted for the higher levels of ethnic identification reported by women in mixed-ethnicity marriages thinking about their mother compared to women in mixed-ethnicity marriages thinking about their spouse. Greater shared understanding of ethnicity with spouse accounted for the higher levels of ethnic identification reported by women in same-ethnicity marriages compared to women in mixed-ethnicity marriages...