Low life satisfaction among multicultural children is an important issue related to children’s mental health in Korea. The purpose of this study was to identify factors influencing the life satisfaction of children whose Vietnamese mothers migrated to Korea for marriage. Data from the Multicultural Adolescents Panel Study (MAPS) conducted by the National Youth Policy Institute (NYPI) in 2020 were used. The participants were 586 elementary school students. The mean age was 11.01 years (SD 0.19), and 52.0% were girls. Based on Engel’s biopsychosocial (BPS) model, biological factors (gender, physical health, and body mass index), psychological factors (mental health, acculturative stress, self-esteem, and general stress), and sociocultural factors (family economic status, social support, and parenting style) were measured and analyzed by using hierarchical multiple regression. In the final model, self-esteem (β = 0.399, p
< 0.001), parental social support (β = 0.184, p
< 0.001), and neglectful parenting style (β = 0.085, p
= 0.031) were positively related to children’s life satisfaction, whereas general stress (β = −0.213, p
< 0.001) and acculturative stress (β = −0.104, p
= 0.002) were negatively related. The overall explanatory power was 41.7%. In conclusion, it is necessary to develop a specialized program that focuses on strengthening the bonds between parents and their children to enhance family functioning for multicultural families.