This study aims to answer the problem of the effect of transformational leadership on organizational commitment at PT. Indonesian jewel. In a company, employee commitment is a valuable asset that can give good results to a company. If employees have good commitment, all of the company's vision and mission will run well. One of the factors that can provide positive things in building commitment is transformational leadership. Some theories put forward by experts on organizational commitment According to Lincoln (in Sopiah, 2008: 155), organizational commitment includes member pride, member loyalty, and member willingness to the organization. As for the transformational one, Bass (in Wutun, 2001: 350) states that transformational leadership is a leadership style that tends to build awareness of his subordinates about the importance of the value of their work and duties. The population to conduct the research was composed by 110 respondents, by first conducting a tryout test to 30 respondents, the study was carried out by distributing the scale to 80 respondents, by dividing two scales, namely, the scale of organizational commitment totaling 28 items and the scale of transformational leadership totaling 28 items, after the validity test and reliability became 27 items of transformational leadership, while organizational commitment amounted to 16 items. This study uses statistical regression test calculations. Based on the regression equation ΕΆ = 30.258 + 0.351, it can be read that every one unit increase in the transformational leadership score will increase the value (Y) of organizational commitment by 0.351 at a constant of 30.258 or in other words, the stronger transformational leadership, the stronger organizational commitment. It can be seen that the Transformational leadership regression on commitment is t = 12.148 with a significance of 0.00
