This research aims to examine the impact of transformational leadership on organizational commitment as mediated by job stress and job satisfaction in construction service companies, PT Wijaya Karya (Persero) Tbk. This study uses explanatory research with a quantitative approach. The samples used in this study are 344 respondents of PT Wijaya Karya (Persero) Tbk’s employees.  The purposive sampling method is the sampling technique in this study. The data were analyzed using structural equation modeling partial least squares (SEM-PLS). The results of this study indicate that transformational leadership can increase organizational commitment, control job stress, and increase job satisfaction. The leader of companies needs to improve transformational leadership. It performs an essential role in increasing employee commitment. The results of this study also found that the mediation of job stress and job satisfaction was a partial mediation between transformational leadership and organizational commitment.