This thesis aims to critique the Universal Declaration of the Rights of Mother Earth and its underlying moral justification in order to provide a stronger and improved version of both. In Chapter 1 I explore what sort of moral justification is necessary to establish the Universal Declaration on firm grounds and explore its relation to environmental ethics and rights discourse. I argue that a non-anthropocentric perspective is necessary to justify the Universal Declaration’s rights. In Chapter 2 I explore the underlying justification of the Universal Declaration as discovered in the works of Cormac Cullinan and Father Thomas Berry. I argue that their ethical framework is indeterminate, has many ambiguities and uncertainties, and, among other problems, it does not provide a clear action-guiding framework. In Chapter 3 I develop an alternative justification for the Universal Declaration. I argue against many predominant moral theories, that in light of our best scientific and moral understanding we should expand the realm of moral concern to include all living beings, a moral theory I call Life’s Imperative. In Chapter 4 I illustrate that Life’s Imperative is a much stronger, more coherent justification for the Universal Declaration, one that coheres with both our best understanding of the natural world and our relation to it, and to an environmental ethic reflective of that relationship. Unfortunately many of the weaknesses in the current implicit justification of the Universal Declaration have also led to it enshrining rights that are themselves problematic. In order to address these issues, I revise its rights to accord with the stronger justification that I established in Chapter 3. The end result of doing so is a revised version of the Universal Declaration