The purpose of this study is to examine the job stress in Korean middle school teachers and to examine factors that affect the job stress of teachers. To this end, using TALIS 2018, which investigated the job stress of teachers in earnest, we analyzed the status of job stress of Korean teachers. Multiple regression analysis, Random intercept model, and School fixed effect model were applied to Korean data of TALIS 2018 to identify teacher and school characteristic factors that have a statistically significant effect on the job stress. As a result of our analysis, Korean teachers experienced a relatively higher level of job stress than the OECD and TALIS averages, and the job stress was higher among female teachers and low-experienced teachers. As a result of analyzing the factors affecting the job stress, our resutls indicated that the characteristics of teachers such as experience, full-time status, working hours, job motivation, job satisfaction, etc., and school characteristics such as school location, external teacher evaluation, and school climate were found to be related to job stress. Based on the results, this study calls for finding strategies for reducing the job stress by considering the job stress related factors, such as career, full-time status, working hours, job motive, job satisfaction, school location, external teacher evaluation, and school climate. In particular, it was emphasized that it is necessary to continuously make efforts to relieve the job stress of teachers by seeking ways to increase teachers' satisfaction with their teaching jobs and to strengthen positive perceptions of their social status.