Organisations (civil society, companies, and public-sector organisations (PSOs)) have been instrumental in driving sustainability. In the last five years, there has been an increasing interest in organisational sustainability, where the importance of sustainability's dimensions depends on an organisation's nature and purpose. A large body of literature on organisational sustainability has focused on companies, followed by education institutions, in particular higher education. Limited, yet increasing, attention has been directed to PSOs and other civil society organisations. Although there have been some attempts to define a sustainable organisation, there is still a need to define and establish the principles of how organisations can address and contribute to sustainability. The sustainability efforts in the different types of organisations were reviewed and then analysed in this paper by using hermeneutics. This was complemented with a survey on sustainability changes. The survey was sent to a database of 1574 contacts from different organisations. In addition, 106 anonymous links were sent out. From the total list of emails, 118 full responses were obtained, with 39 from civil society (37 from higher education and 2 NGOs), 66 corporations, and 13 PSOs. This research distils the key system elements of the efforts in each of the organisations in order to synthesise and propose a definition and a conceptual framework of organisational sustainability. These can help organisations understand where their efforts are and how they could better embed sustainability into their systems, thus contributing to the well-being of societies and the environment for this generation and future ones.