This dissertation provides a systematic analysis of when an individual or group has a right to secede that is grounded in self-determination. Since the primary question in a secessionist conflict concerns the territory being contested, any analysis of the right to secede must provide an account of what grounds the existing state's claim to political jurisdiction over its territory. With this in mind, I examine consent and teleological justifications for the state and find both inadequate. The consent account posits that a political state is justified just in case it has the consent of its citizens. I reject the consent approach for its unacceptable implication that unlimited secession is permissible from all existing states. I then suggest that our disinclination to allow unlimited secession is instructive since it indicates not only that we believe a consentual justification is morally unnecessary, but also that a state is justified in virtue of the peace it secures and the rights it protects. This teleological justification ultimately proves inadequate as well, however, because it both restricts secessionist movements that seem permissible and allows coercive annexations that appear clearly unjustified. As an alternative to these extremes, I propose a hybrid model of political legitimacy. According to my theory, while individuals and small groups may not secede, a larger group may, provided it is of sufficient size to satisfactorily perform the functions that are necessary for a state to ground its claim to territory. Thus I conclude a political state should limit political liberty in a manner analogous to the way it legitimately limits the liberty to drive a car. Specifically, since many people would be harmed if there were no legal restrictions on who could drive, states institute age and health requirements limiting who may drive. Citizens not eliminated by these standards must also demonstrate a minimum threshold of competence by passing tests. In similar fashion, a state may initially restrict the right to secede to groups of a specific size, and then further require that interested parties demonstrate their ability and willingness to govern in a stable, efficient, and liberal manner