This study examined the predictors of turnover intentions among middle school teachers in South Korea, using data from the 2018 Teaching and Learning International Survey (TALIS). Here, the turnover intention was operationalized as the intention to leave the teaching profession in the next five years. Results showed that the proportion of those who are likely to leave the teaching profession in the next five years among Korean middle school teachers was approximately 25%. This likelihood, however, significantly differed by the age groups. For example, the proportion of those who are likely to leave the teaching profession in the next five years was approximately 3% among early career teachers in their 20s, but the corresponding proportion was 60% among teachers in their 50s. On the other hand, the lower level of satisfaction with teaching profession was associated with the increased likelihood of teachers’ turnover intentions for all age groups, with other things being equal. For teachers in their 40s, job stress was another significant predictor of teachers’ turnover intentions. For teachers in their 50s, having a graduate degree and longer teaching experiences were additionally associated with the increased likelihood of teachers’ turnover intentions. Policy implications were discussed.