Kim Kyung Ryung. 2012. A study of influencing variables for multicultural family children`s Korean proficiency. Journal of Korean Language Education 23-2: 1-37. This study examines social variables which influence multicultural family children`s language development in Korea. 197 elementary school students who have a multicultural family background participated for this study. Subjects participated for Korean accuracy test and answered survey questionnaire. In order to get a reliability and credibility, pretest was activated. Findings are as below. First, among various social variables, role of Korean father seems to be very important to increase children`s Korean language acquisition. Second, Specialized teachers who were sent by the Korean government for multicultural family were very helpful for children`s language development. Third, children who have active interaction with family members, school friends and people meeting at religious place shows high level of Korean proficiency. Fourth, immigrant mother`s language background influenced to children`s language accuracy. Both immigrant mother and children share similar tendency making error at similar grammatical categories. Fifth, code switching did not influence to increase or decrease language accuracy.