Despite a few local studies on the higher education governance model, there has been scant research into the underlying link between organizational structure change and employee job performance in Ethiopian research universities. This study assessed the relationship between organizational structure change and staff job performance at Addis Ababa University (AAU). This study employed cross-sectional and quantitative survey approaches. The research used 242 randomly selected academic and non-academic staff to complete the questionnaire. The analysis employed descriptive statistics such as regression, correlation, and the independent t-test, as well as inferential statistics like exploratory factor analyses and structural equation modeling. The results show a significant positive correlation between staff job performance and dimensions of organizational structure like decision-making, job codification, and authority hierarchy. The findings also revealed that all organizational structural change factors influence the dimensions of staff job performance except the rule observance dimension. The university's organizational structure has a moderate change that improves workers' job performance. Therefore, the study suggests that management should enhance staff decision participation, autonomy, and rule flexibility while fostering a flatter organizational structure.