This thesis will consider the role and definition of conscience and unconscionability in English equity. Whilst conscience is at the heart of equity, surprisingly little has been written, either academically or juridically, about how equity uses and defines unconscionability. It is this significant gap that the thesis seeks to fill. The thesis will ask and answer three questions. The first is how does equity conceptualise conscience? The thesis will demonstrate that equity adopts an objective conception of conscience, which is a modified version of the scholastic conception of conscience, which was used by the medieval Church. The second question is asking what the role of conscience in equity is. The thesis will demonstrate that the role of conscience is to provide an objective moral baseline by which to judge all parties. Conscience also has an important role to play in expanding, developing and adapting existing equitable principles to new circumstances. The third question is identifying the definition of unconscionability. This is done both by looking at some of the few existing academic writings on conscience as well as case studies on some of the major equitable claims, including breach of fiduciary duties and constructive trusts. The thesis offers a range of unconscionability indicia, which, taken together, outlines the meaning of unconscionability. The aim of the thesis is to provide greater clarity into how equity operates and how it uses its conscience. This will be of use to judges, lawyers, and academics (and indeed law students) and will address the critics of equity who posit that conscience is subjective, vague, and leads to arbitrary and capricious judgments. With this clear definition, it will be demonstrated that equity is not subjective, nor vague, nor arbitrary, but rather provides a clearly identified path to justice.