Teachers in South Korean schools have begun to pay attention to the importance of multicultural education as Korea transforms into a multicultural society from a historically mono culture society. Because of Koreans' pride in the homogeneity of their race, language, and culture, multiculturalism is an idea that is hard for many to accept. Education needs to play a key role in fostering and retaining the value of diversity. Studies suggest that teachers' positive beliefs about diversity play a significant role to develop their multicultural competence and eventually to practice better multicultural education. The problem is little evidence exists in the literature about Korean teachers' beliefs about diversity. The purpose of this study was to examine South Korean teachers' beliefs about diversity, the factors that influence those beliefs, and the impact of those beliefs on their practice of multicultural education teaching. I used a mixed methods research approach which included surveys among a group of elementary teachers in South Korea and interviews with six teachers to examine their beliefs about diversity in more depth. Results indicated that for teachers in this study: (a) intercultural experiences positively influenced Korean teachers' beliefs about diversity; and (b) teachers' beliefs about diversity had a significant impact on their practice of multicultural teaching. Based on the findings, I suggest that teacher education programs provide meaningful intercultural experiences and support teachers to develop positive beliefs about diversity, and eventually, to practice better multicultural education in South Korea.