This paper starts from the recognition that we need to understand the competency-based education in the context of Korean language education. Hence this paper tried to clarify the meaning and structure of relation among Korean language ability, Korean language key competence and cross-curricular key competence. A comparison was made between the Korean language ability and the Korean language key competence and an analysis was done on the meaning of Korean language key competence Lastly, the paper explored the relations of Korean language key competence and cross-curricular key competence. The Korean language ability and the Korean language key competence have a common goal in achieving important abilities through Korean language education. However, there are differences in modes and perspectives of getting access to the Korean language ability and the Korean language key competence. This paper found that previous and current discussions and papers on the Korean language ability mostly reflected the perspectives based on the linguistics or the general cognition and approached in a construct analysis method. In comparison, the Korean Language key competence should reflect the perspectives based on current demands in the society and the holistic approaches in performance abilities. This broadened concept encompasses current expectations and demands from the society. In addition, its autonomy and unique characteristics should be respected in relation to the cross-curricular key competence and the Korean language key competence should be able to support the cross-curricular key competence in a harmonious way.