This study aims to investigate the effect of school administrators’ personal initiative behaviors and their leadership styles on teacher motivation. In this study, designed with a quantitative research approach, the relational scanning model was used, and a model was created to test the effect of school administrators’ leadership styles and personal initiative behaviors on teacher motivation. In this context, the leadership styles of school administrators and their personal initiative behaviors were studied as independent variables, while teacher motivation was studied as a dependent variable. In the study, 406 teachers working in high schools in Manisa city center were selected using the purposeful sampling method. Pearson moment correlation techniques and multiple regression analysis techniques were used to determine whether there was a significant relationship between dependent and independent variables during the data analysis. According to the results obtained from the research findings, it was observed that the general motivation levels of the teachers were high. In the analyses conducted in terms of the relationships between school administrators’ personal initiative-taking behaviors and teachers’ motivation, it was found that these variables had a significant and positive relationship; similarly, it was determined that there is a significant relationship between the leadership styles of school administrators and the motivation of teachers. In the regression model established to examine the effect of the leadership styles of school administrators on the internal factor dimensions of teacher motivation, it was determined that all sub-dimensions of leadership styles predicted teachers’ internal motivation. This research provides evidence that school administrators’ personal initiative behavior is directly related to teacher motivation and positively affects teacher motivation, thereby affecting the quality of their teaching.