Transformational leadership is seen as a mediator of employee voice behavior. This study attempts to investigate the influence of leadership style as an organizational variable that can motivate employee voice behavior and expand understanding of the relationship between personal characteristics and employee voice. The research was conducted among public sector employees online. A total of 410 questionnaires were collected. After the elimination of invalid questionnaires, 356 questionnaires were received. For data processing, we used the six-item Employee Voice Questionnaire, the 17-item Proactive Personality Scale (PPS), and the Multifactor Leadership Questionnaire (MLQ- 5S). The result shows that leadership style as an important organizational variable helps employees with a proactive personality to show more positive behavior. Transformational leadership style positively and significantly moderates the relationship between proactive personality and employee voice.