World Heritage sites are irreplaceable tourist destinations. These protected areas face many challenges and issues, which impact on their Organizational Behaviour (OB) and sustainability. World Heritage status holds considerable promise for economic and social growth, sustainability and development. To this effect UNESCO’S World Heritage Convention ensures that heritage sites around the world are recognized and protected and encourages participatory management. However, many organizational factors may negatively influence sustainability, for example the management or decisions-making style and fragmentation or miscommunication between stakeholders. World Heritage Sites are organizational groupings of stakeholders working together to achieve goals. OB views organizations as open systems with interrelated parts, interacting with the environment and influenced by organizational design, dynamics and stakeholder relationships. The primary objective of this study was to investigate the strategic level of OB of selected World Heritage sites in South Africa, namely the iSimangaliso Wetland Park and the Cradle of Humankind, in order to develop a Strategic Organizational Behaviour Framework to facilitate effective management and sustainability. An exploratory qualitative research approach provided rich descriptive data. The empirical phase involved non-probability sampling and data collection focusing on in-depth interviews with key stakeholders. The findings indicate that the manner in which World Heritage sites are managed influence the organizational culture, communication and the stakeholder relationships. There is a perceived discrepancy between ‘ideal’ OB and the actual experiences of the stakeholders. Issues of strategic concern were the organizational design and structure, in both cases found to exclude key stakeholders; the management style and behaviour, found to be mainly dictatorial and exclusive; and the organizational culture and communication, influenced by the particular management of the sites and experienced as closed and non-participatory. The relationships between strategic stakeholders were found to be flawed, resulting in the sustainability of these sites being questioned. The Strategic OB Framework developed here, is based on OB and Open Systems Theory principles and illustrates the interdependency and influence of the different strategic OB dimensions. Management must understand that positive organizational design, dynamics and relationships will lead to more effective management and sustainability. This Strategic OB Framework can inform management and contribute significantly to sustain the effective management and the continued success of World Heritage sites in South Africa.