This study aims to investigate into how children audience is considered in the translation of family musical theatres—targeting both children and adult audience—which are gaining greater attention as a new opportunity to overcome the stalled South Korean musical market after the exponential growth of as much as 2,400% from 2001 to 2015. Based on factors affecting the translation of musical theatres and children’s literature, this study analyzed how the lyrics of Matilda the Musical were translated in consideration of children audience when it was premiered in South Korea as its first-ever non-English production. Findings show that onomatopoeia and mimetic words are used, ST structures are simplified and streamlined, and ST forms are changed to help the understanding and attract the interest of children audience as in the case of children’s literature. However, slangs and neologisms are frequently used to amplify the emotional effect, which can have an adverse impact on children’s education and emotional development. Such strategies are possibly adopted to resonate with Korean adult audience who is the major ticket buyers and tends to be lured to the dramatic development of a story and intense emotional experience.