Higher Education Institutions play an important role in the promotion of sustainability and an increasing number of stakeholders expect them to be sustainable organizations. However, this can only be achieved when barriers are faced and challenges overcome. This exploratory study aims to investigate how the main stakeholders (leaders, faculty, staff, students, and external stakeholders) of Portuguese Public Higher Education Institutions perceive: the concepts of sustainability and sustainable higher education institutions, the role of higher education for sustainable development, and the barriers, challenges and obstacles to implementing sustainable initiatives in Portuguese Public Higher Education Institutions. Through a qualitative approach, using semi-structured interviews and content analysis procedures, this article explore the perspectives of twenty stakeholders from four Portuguese Public Higher Education Institutions. The results suggest that, although aware of the concept of sustainability, the different stakeholders are not familiar with the concept of sustainable higher education institutions. The lack of financial resources due to the decline in funding for higher education and falling numbers of Portuguese university students is perceived as the main barrier to sustainable development in higher education (i.e. practices are still associated with spending financial resources). This research highlights the importance of a conceptual and organizational change in higher education institutions, notably through identifying new sources of financing, more flexible organizational forms, more comprehensive mission statements, more tailored educational offers, life-long learning and commitment to internationalization, and more strategic human resource management. The paper contributes to the literature by reflecting on how higher education institutions can promote sustainability, how higher education for sustainable development is understood and can be improved in Portuguese Higher Education Institutions.