Background: Multicultural families and foreign residents are rapidly increasing in Korea. Thus, the proportion of children and adolescents from minority racial/ethnic groups are also increasing, and there are concerns about adolescents who fail to adapt to school and show low academic achievement and poor health status. Objective: This study aimed to investigate influencing factors related to academic achievement among Korean multicultural adolescents. Methods: Cross-sectional data from 2234 Korean multicultural adolescent participants from the 2010-2014 Korea Youth Risk Behavior Web-based Survey were analyzed using multiple regression. Results: Perceived economic status and breakfast frequency affected academic achievement, regardless of gender. Family affluence, satisfaction with sleep time, and lifetime smoking were additional factors in males. For females, depression and frequency of physical school activities were additional factors. Conclusion: The present study suggests that diverse individual factors should be considered, including economic status, health status, and health-related behaviors, to improve multicultural adolescents' academic achievement.