摘要：The objective of this study is to describe the influence of principals' leadership, work environment, and affiliation motivation on improving the performance of certified teachers at Private Vocational Schools in Tegal City, Indonesia. To achieve this objective, the current study carried out a research survey in Private Vocational Schools of Tegal City. Therefore, data collection was achieved by using survey questionnaire and respondents of the study was school teachers. Thus, this study used quantitative research approach with cross-sectional research design. Data were analyzed by using latest technique, namely; Structural Equation Modeling (SEM) based on Partial Least Square (PLS). The results of the study showed that the leadership of the principal, the work environment, and the motivation to affiliate were well per-ceived by the teachers. Both principal leadership and work environment had direct effects on improving the certified teacher’s performance. The teacher’s performance can be explained by independent head leadership and work environment variables, however, for independent variables namely; motivation to affiliate did not have enough significant influence. Hence, teacher’s performance can be improved through the leadership of principals and a conducive work environment.
