The purpose of this study was to develop the scale of musical communication competency for middle-school students and explore its related variables. After a pilot study, the instrument of 23 items, which consisted of music knowledge, expression, appreciation, and application, was developed. For the scale, content validity and explorative factor analysis were made, and Cronbach s α (.956) proved the reliability of the scale. Also, students gender, the experience of music lessons out of school, perception of his/her own musical talent, communication in music group class, and preference for participation in music performances were found to be related to musical communication competency.