The purpose of this school action research is to determine the increase in the ability of teachers in making completeness of online learning tools through the supervision of the Principal at SD Negeri 40 Mataram for the 2020/2021 academic year. Based on the results of the analysis and discussion of cycle I and cycle II above, it can be concluded that: Through the supervision of the Principal at SD Negeri 40 Mataram in the 2020/2021 school year, the teacher's ability to make complete online learning devices has increased significantly. If in the first cycle the total average score of the teacher only increased from the first cycle, namely the percentage of completeness 66.67% and 88.89% in the second cycle the teacher was generally said to be complete with the total increase in the average score of teachers was 8.67 and the total percentage increase was 22.22%, this shows that the improvement efforts carried out by researchers in the second cycle brought changes. Effective academic supervision is used to increase the competence of teachers at SD Negeri 40 Mataram in making completeness of online learning tools.