This thesis discusses the meaning of the right to self-determination in its historical and contemporary perspective, and examines the different options available for the accommodation of contested self-determination claims. Arguably, the creation of new States and secession are amongst the most significant and controversial issues pertaining to self-determination beyond the colonial context. Detailing these implications in relation to the Iraqi Kurdistan Region (IKR), the thesis argues that even if secession is one mechanism to resolve self-determination disputes, this does not do away with the need to continue exploring a new conflict settlement approach as an alternative to extremist secession. The proposed ‘Remedial Earned Sovereignty’ (RES) approach affords a way of assessing post-colonial breakaway movements in their different manifestations. A new entity may come into being lawfully through negotiated and consensual constitutional processes. The RES approach allows another layer of consideration to be added that goes beyond the superficiality of pure ‘legality’, by delving into the legitimacy of the new entity. It will argue that legitimacy is a second layer of essential consideration, and it involves a deeper and more holistic level of analysis. Significantly, the thesis will argue for a need to look at the circumstances that led to the secession and State creation, and also at how the entity has conducted itself, and how it has organised itself internally. It demonstrates that outside the colonial context the emergence of a new State is not a matter of meeting the statehood criteria, but rather a politically realised legal status. Accordingly, in order to navigate through these considerations of legality and legitimacy, a set of guidelines for States in assessing how to deal with entities coming into existence because of secession have been suggested. This is dubbed a ‘Remedial Approach to Post-Colonial External Self Determination’. The thesis will then apply and refine the remedial approach to post-colonial external self-determination in the cases of Kosovo, Quebec and South Sudan, and ultimately test the finalised hypothesis idea on the IKR. This Thesis is based on the situation up to October 2014