In this article, we tested if female adopted Chinese youth's sense of exclusion predicted their behavioral adjustment and mental disorder diagnoses concurrently (Study 1) and longitudinally 5 years later (Study 2). In Study 1, 224 adoptees (M = 13.6 years, SD = 2.1) provided survey data on sense of exclusion (as indexed by ethnic marginality, ethnic identity search, and negative feelings toward adoption) and Internalizing Problems (i.e., anxiety, withdrawal, and somatic complaints), measured with the Child Behavior Checklist (CBCL)-Youth Self-Report.In Study 1, the adoptive parents additionally completed the CBCL parent-report on the adopted children's Internalizing Problems and reported if the adopted children had any mental disorder diagnoses. In Study 2, 60 youth from Study 1 (M = 18.6 years, SD = 2.1) completed the 3rd edition of the Behavioral Assessment System for Children-Self Report of Personality (BASC-3-SRP) that measures School Problems (i.e., negative attitudes toward teacher, negative attitudes toward school, and sensation seeking), Internalizing Problems (i.e., atypicality, locus of control, social stress, anxiety, depression, sense of inadequacy, and somatization), Attention-Deficit/Hyperactivity Disorder (ADHD; i.e., inattention and hyperactivity), and Personal Adjustment (i.e., relations with parents, peer relations, self-esteem, and self-reliance). They also responded to questions on receiving mental disorder diagnoses and treatments. We found that in Study 1, 33.2% of the youth had at least one diagnosis, with Anxiety Disorder (21.4%), ADD/ADHD (16.7%), and Attachment Disorder (7.5%) being the top three disorders. In Study 2, 40.3% had at least one diagnosis, with Anxiety Disorder (25.0%), Depression (21.7%), and ADD/ADHD (16.7%) being the top three disorders. Path analyses showed that in Study 1, ethnic marginality and negative feelings about adoption, but not ethnic identity search, significantly predicted parent-reported and self-reported Internalizing Problems; in Study 2, none of the three indicators of sense of exclusion predicted the adopted youth's adjustment.