This thesis is focussed on the development and implementation of a Relationships Framework based on Te Tiriti/Treaty of Waitangi. The Framework has been designed to enable working together between Tangata Whenua and Tangata Tiriti in the community and Public Sector in Aotearoa New Zealand. Its development is explored and its implementation critiqued. Within that Framework, an original organisation development tool based on a Tiriti/Treaty two-worldview approach is examined in terms of its potential to facilitate change in the operation and management of public life in Aotearoa New Zealand. My aim is to establish an effective approach for working with worldview difference in the context of Tiriti/Treaty of Waitangi relationships and their implications. I have a belief that Tangata Whenua are currently excluded from participating in processes that govern public life due to the dominance of Tangata Tiriti worldviews. Therefore I am committed to making a contribution to a change in this dynamic so that Tangata Whenua views are not only heard but form an integral part of how the infrastructure of our public life is developed and managed. The Tiriti/Treaty of Waitangi Relationships Framework [The Framework] presented in the thesis is critiqued in two ways: i) through an examination of the concepts that inform it, and ii) by exploring six examples of its operation and further development in the community and public sector in Aotearoa New Zealand. The Framework and the Tiriti/Treaty Two-worldview approach used to inform it has worked effectively in a variety of settings. Through my research I show that organisation development of this type is complex. It appears that there need be no fixed starting point in the development process within an organisation. However all key elements of that process must eventually be addressed if effective relationships are to be achieved and the resulting organisational change is to be sustained. Commitment to organisation development of this type is therefore long-term and requires a commitment to leading and supporting change in behaviour, systems and processes, and structures.