The Questionnaire about Interpersonal Difficulties for Adolescents (QIDA) is a self-report instrument designed to measure adolescents' perceived interpersonal anxiety levels in a wide range of relationships with people of different ages, genders, levels of authority, and levels of intimacy and in several contexts: family, school, friends, opposite sex peers, and situations in the streets, shops, and public buildings. The QIDA provides important information for adolescents, educational and clinical psychologists, and researchers. This instrument can be used as a screening measure to identify social situations and relationships that adolescents find troublesome so that important target areas for social skills training programs can be ascertained. Thus, the QIDA can be used as a counseling tool for adolescent advising and for interpersonal difficulties remediation or prevention programs in a variety of clinical, educational, and research settings, including schools, counseling and mental health centers, alcohol and other drug units for youth, correctional and social service agencies, and research centers. In this study, the factor structure of the QIDA was examined across gender and ethnicity in samples of Spanish and Chinese adolescents using multigroup confirmatory factor analyses. Partial invariance was observed across gender in the Spanish sample and across ethnic groups. Measurement invariance was found across gender in the Chinese sample. (Contains 3 tables and 1 figure.)