Using the systematic approach, we reviewed the characteristics (trend, method, school, and major) of studies on WAC conducted in South Korea thus far. In particular, we considered how these studies defined the concept of WAC. In summary, the findings were as follows: the total number of studies conducted on WAC in South Korea remains very small (N = 25). Among data-based empirical studies, the proportion of articles using qualitative methods is much higher than those relying on quantitative methods. Most studies refer to WAC at the college level, but some research at the elementary school level is also available. In addition, most studies applied WAC to classes related to the humanities and the social sciences. In Korean, translation the most used term for WAC was ‘범교과적 글쓰기’, and most articles defined the concept of WAC clearly. When the concept is clearly explained, most research defined WAC without quoting the definitions of others but devising their own. The definitions of WAC differed slightly according to different focuses, but basically emphasized that writing should be an important element of education in various majors and liberal arts curricula. Based on this systematic literature review, we propose the following two discussions.