Organizations need to execute a number of projects simultaneously in order to react market changes. Besides that, technological advancements enable large scale, complex projects feasible. Keeping all these projects under control and executing projects effectively is a serious problem for every organization. PMOs are appeared to be a solution for managing multi-project environments, but their contribution to organizations is tortuous. In this research, activity areas of PMOs are derived from existing works, and the relationships between PMO activity areas and stakeholder's satisfaction are investigated by applying PLS-SEM methodology. There are six activity areas defined, and named as "project procurement", "knowledge management", "project team management", "communication", "project planning & follow up", and "development and maintenance of IT". With the guidance of existing literature research model is developed. Results show that " project planning & follow up", and "project procurement" activities have direct effect on "stakeholder satisfaction" at medium level. Besides that, "knowledge management" and "IT infrastructure" have indirect effect through " project planning & follow up".