The purpose of this study is to explore how English instructors at a Korean university utilized the CANVAS learning management system (LMS) when teaching EFL academic writing classes online, and their perceptions of its effectiveness and limitations. Seventeen instructors working at a university located on the outskirts of Seoul participated. Data were collected through a survey questionnaire consisting of a combination of multiple choice, a 5-point Likert scale, and open ended questions, all of which were used as the primary data collection method. Data analysis was conducted using general qualitative analysis for the open ended questions and descriptive statistics for the multiple choice and 5-point Likert scale questions. The findings of the study indicate such tools and functions as Lecture Contents, Inbox, Announcements, Assignments, Learn Status, Assignment Comment, and Speed Grader were used frequently on CANVAS, which was also related to the instructors’ high levels of satisfaction with this LMS in the areas of sharing course content, managing a classroom (e.g., monitoring students’ learning activities and communicating with students), and administering assignments and exams. On the other hand, the instructors reported that they used such tools and functions as Collaborations and Discussion less on Canvas, which matched their relatively low satisfaction with CANVAS in writing related areas such as grading, giving feedback, sharing peer feedback, and doing collaborative writing activities. Administrational and educational implications of these findings are discussed.